DESCRIPTION OF THE HOLLIDAYSBURG AND HUNTINGDON QUADRANGLES

By Charles Butts

INTRODUCTION 1 BLUE RIDGE PROVINCE topography are therefore prominent ridges separated by deep SITUATION The Blue Ridge province, narrow at its north end in valleys, all trending northeastward. The Hollidaysburg and Huntingdon quadrangles are adjoin­ Virginia and Pennsylvania, is over 60 miles wide in North RELIEF ing areas in the south-central part of Pennsylvania, in Blair, Carolina. It is a rugged region of hills and ridges and deep, The lowest point in the quadrangles is at Huntingdon, Bedford, and Huntingdon Counties. (See fig. 1.) Taken as narrow valleys. The altitude of the higher summits in Vir­ where the altitude of the river bed is about 610 feet above sea ginia is 3,000 to 5,700 feet, and in western North Carolina 79 level, and the highest point is the southern extremity of Brush Mount Mitchell, 6,711 feet high, is the highest point east of Mountain, north of Hollidaysburg, which is 2,520 feet above the Mississippi River. Throughout its extent this province sea level. The extreme relief is thus 1,910 feet. The Alle­ stands up conspicuously above the bordering provinces, from gheny Front and Dunning, Short, Loop, Lock, Tussey, Ter­ each of which it is separated by a steep, broken, rugged front race, and Broadtop Mountains rise boldly 800 to 1,500 feet from 1,000 to 3,000 feet high. In Pennsylvania, however, above the valley bottoms in a distance of 1 to 2 miles and are South Mountain, the northeast end of the Blue Ridge, is less the dominating features of the landscape. The relief in the prominent. The rocks of this province are closely folded broad intervening valleys ranges from 100 to 600 feet but is quartzite, slate, schist, gneiss, granite, and greenstone. generally 200 to 300 feet. VALLEY AND RIDGE PROVINCE 2 PRINCIPAL TOPOGRAPHIC FEATURES The Valley and Ridge province is a belt of country 50 to 80 The Allegheny Front, generally known as Allegheny Moun­ miles wide extending from New York to Alabama in a general tain, the great eastward-facing escarpment of the Appalachian direction about S. 40° W. and bounded by the Blue Ridge on Plateaus, is the most impressive feature of these quadrangles. the southeast and the Appalachian Plateaus on the northwest. It crosses the west side of the Hollidaysburg quadrangle and This belt is characterized by broad valleys separated by high rises to a height of 3,136 feet above sea level in Blue Knob, in ridges trending parallel with the belt. These ridges, however, the southeast corner of the adjoining Ebensburg quadrangle are grouped more along the northwest half of the valley, leav­ (pi. 1). The eastern foothills of this escarpment descend to a 77" 76° ing a broader valley on the southeast side known as the valley continuous with Bald Eagle Valley on the northeast and FIGURE 1. Index map of south-central Pennsylvania and parts of Cumberland Valley in Pennsylvania and the Shenandoah with the valley of Frankstown Branch on the southwest. adjacent States. Valley or the Valley of Virginia on the southeast side of the From a point opposite Hollidaysburg through Altoona this The location of the Hollidaysburg and Huntingdon quadrangles is shown by darker ruling (No. 327). Published folios describing other quadrangles are indicated by lighter ruling belt. In Pennsylvania the Allegheny Front, which bounds valley is known as Logan Valley. Nearly inclosed by Brush, and are listed on the back cover of this folio. the Valley and Ridge province on the west, rises from 1,000 Lock, Loop, and Short Mountains is a deep topographic a unit they are bounded by parallels 40°15' and 40°30' and to 1,500 feet above the main valley levels, but only its highest depression known as Scotch Valley. Point View knob in meridians 78° and 78°30'. Each quadrangle includes one- knobs rise much above the highest of the valley ridges. Blue the northwest corner of the Huntingdon quadrangle is another sixteenth of a "square degree" of the earth's surface, and its Knob, on the Allegheny Front, in the northern part of Bed­ striking topographic feature (pi. 2). The broad lowland area is approximately 228 square miles. These quadrangles ford County, stands 3,136 feet above sea level and 1,500 feet between Lock and Dunning Mountains on the west and form a part of the Appalachian Highlands, which extend from above the surface of Nittany Valley. (See pi. 1.) South Tussey Mountain on the east, known as Morrisons Cove (pi. 3), the Atlantic Coastal Plain on the east to the Interior Plains on Mountain, on the southeast side of the Valley and Ridge is really a somewhat offset continuation of Nittany Valley, the west and from Canada to central Alabama. province, in Franklin, Adams, and Cumberland Counties rises Centre County. Raystown Valley is the broad, undulating, APPALACHIAN HIGHLANDS 1,000 feet above the valley level. Near Big Stone Gap, Va., relatively }ow land between Tussey and Terrace Mountains, the crest of Black Mountain is 3,000 feet above the valley on marked by northeastward-trending narrow ridges and drained SUBDIVISIONS the northwest side, and in northern Tennessee Holston by Raystown Branch of the Juniata River. Southeast of Differences in topography, rocks, and geologic structure Mountain, near the northwest front of the Blue Ridge province, Raystown Valley Terrace Mountain and Sideling Hill with form the basis for a natural division of the Appalachian High­ rises nearly 3,000 feet above the valley on the southeast side. the north end of Broad Top Mountain, which together inclose lands into several parts called provinces. These are, from These features are exhibited in the profile section of Figure 2. the Great Trough Creek Valley (pi. 4), are the principal southeast to northwest, the Piedmont province, the Blue Ridge The rocks in these quadrangles, as in the entire Valley and topographic features. province, the Valley and Ridge province, and the Appalachian Ridge province, are limestone, dolomite, conglomerate, sand­ All the great ridges are caused by hard sandstones which, Plateaus. The boundaries of these provinces are shown on stone, and shale, which have been greatly disturbed by folding with the exception of that forming the summit of the Alle­ Figure 2. West of the Appalachian Plateaus are the Interior and faulting. gheny Front, are steeply inclined. The softer shales and the APPALACHIAN PLATEAUS soluble limestones have been eroded away faster than the hard sandstones, which are left in high relief. The slopes of these The Appalachian Plateaus, which are practically coextensive ridges in places are more than 20°, as for example the east with the Appalachian coal fields, are relatively high, ranging slope of Loop Mountain near the middle, where there is a from 800 feet above sea level in parts of Alabama to more than descent of 1,200 feet in half a mile. About the middle of 4,500 feet in Pocahontas County, W. Va., whence they descend the southeast slope of Lock and Dunning Mountains and the through Pennsylvania to about 2,000 feet in western New northwest slope of Tussey Mountain is a series of flat-topped York. Sandstone, conglomerate, shale, and coal beds make spurs, which are formed by another hard sandstone cropping up most of the rocks of the Appalachian Plateaus. In con­ out at that level. The coincidence of these features of relief trast with those of the Valley and Ridge province the strata of with the outcrpps of the several hard sandstone formations is the plateau province have been but slightly disturbed from clearly displayed on the geologic maps. their original horizontal attitude. A notable feature of the ridges is their parallelism, which is TOPOGRAPHY due to the geologic structure. (See pi. 5.) All the ridges are essentially hogbacks, the Allegheny Front, Dunning Mountain, The Hollidaysburg and Huntingdon quadrangles lie in a and some minor ridges being on the west limb and Tussey and region of mature topography. The great limestone valley Terrace Mountains- on the east limb of the great Nittany arch. between Dunning and Tussey Mountains has advanced to the (See structure sections.) Sideling Hill is a hogback on the FIGURE 2. Map of the central part of the Appalachian Highlands stage of early old age, as shown by the complete adjustment of Jacks Mountain anticline, whose crest is just east of the showing its physiographic divisions. the drainage as to both the distribution of the streams and the southeast corner of the Huntingdon quadrangle. (See pi. 6.) Low Plateaus, which are included in the Interior Plains by gradation of their beds. The stream beds are nearly free from Dunning and Tussey Mountains and Sideling Hill are sym­ the United States Geological Survey but which in the opinion rock shoals and waterfalls, and uniform slopes prevail in them. metrical, having equal slopes on their two sides, owing to the of some, of whom the writer is one, should be included in the The extremes of relief are considerable, and there is a moderate erect attitude of the rocks; the Allegheny Front and Terrace Appalachian Highlands. degree of diversity in surface forms. The dependence of Mountain are unsymmetrical, having steep slopes facing the topography upon the lithologic character and the attitude of Nittany arch and low slopes facing in the opposite directions, PIEDMONT PKOVINCE the underlying strata is abundantly and strikingly illustrated. owing to the low dip of the strata in those directions. The Piedmont province is a rolling upland 1,100 feet above The quadrangles lie almost wholly in the Valley and Ridge Several deep gaps or notches through the high ridges are sea level at the east foot of the Blue Ridge and 500 feet or less province, in the belt of ridges along its west side. The north­ notable features of the topography. The largest of these are above sea level along the "fall line." Its generally flat surface west corner of the Hollidaysburg quadrangle lies in the McKee Gap, 800 feet deep, and Point View Gap, 900 feet has been deeply trenched by the streams that flow across it. Appalachian Plateaus. The characteristic features of the deep, through the Dunning-Lock Mountain ridge; Trough Most of its area is underlain by very ancient and crumpled 8 The Valley and Ridge province has long been known as the Appalach­ Creek Gap, 900 feet deep, and Tatman Gap, 700 feet deep, crystalline rocks, both igneous and metamorphic. ian Valley because in general it is lower than the margins of the bounding provinces on each side. In all discussions of mountain systems throughout through Terrace Mountain; and Burgoon and Sugar Run 1 Field work on the Hollidaysburg and Huntingdon quadrangles was the world this belt is designated "the Appalachians/' because it is the Gaps, each about 1,000 feet deep, through the Allegheny done in 1908, 1913, and 1915. The text was written shortly thereafter, but worn-down remains of a once mighty mountain system. Although recog­ Front. The origin of these features is explained under publication was unavoidably delayed. Later publication has involved nizing the appropriateness of the descriptive designation Valley and Ridge some revision. province, the present writer prefers the old name Appalachian Valley. "Geologic history." The topographic maps show that the highest ridges and the At Waynesboro, in Franklin County, the formation is 1,000 Thickness. The thickness of the Warrior limestone is 1,250 crest of the Allegheny Front approach a common altitude of to 1,500 feet thick. feet. 2,000 to 2,400 feet; the foothills of the Allegheny Front and Age and correlation. According to Stose, the upper part of Age and correlation. The Warrior limestone carries cryp- the liat-topped spurs on the east side of Lock and Dunning the Waynesboro in Franklin County is composed of shale, tozoons (see pis. 7-9), brachiopods, and trilobites but not Mountains and the west side of Tussey Mountain approach a part of it purple, and sandstone. The beds described here in abundance. Collections have been made in the southwest­ common altitude of 1,600 to 1,750 feet; and the general alti­ have a similar lithologic character and the same stratigraphic ern part of the Hollidaysburg quadrangle and the adjoining tude of Morrisons Cove and Raystown Valley is 1,200 to position, which justify their identification as Waynesboro. northwestern part of the Everett quadrangle, on the bluff of 1,400 feet. The summits of the high ridges, the spurs and The fossils include Olenellus, Bonniaf, and Hyolithes communist. Frankstown Branch between Williamsburg and Ganister. at terraces at 1,600 to 1,750 feet, and the tracts at the next lower The Waynesboro is correlated with the Rome formation of the points on the road along Warriorsmark Creek within 2 miles level (Morrisons Cove, etc.) are believed possibly to be rem­ southern Appalachian region, which, because it carries Olenellus southeast of Warriorsmark, north of the Huntingdon quad­ nants of former more or less extensive peneplains, the highest and other genera of the same family, is classed as Lower rangle, and within a radius of a mile or two southeast to south­ of which is the Kittatinny peneplain, named from Kittatinny Cambrian. west of Waddle, in the Bellefonte quadrangle, Centre County. Mountain, in New Jersey; the intermediate one the Schooley PLEASANT HILL LIMESTONE From these localities probably as many as 20 species of peneplain, named from Schooley Mountain, in New Jersey; Name and definition. The Pleasant Hill limestone was trilobites belonging to several genera have been collected and and the lowest one the Harrisburg peneplain, named from the named for the excellent exposures of its upper part at Pleasant examined by Walcott, Ulricb, and Resser, and a few species Harrisburg region, Pennsylvania. The origin of these features Hill Church, 1 mile northwest of Henrietta. It is underlain have been identified. The following species have been de­ is explained under "Geologic history." by the Waynesboro formation and overlain by the Warrior scribed from this formation: Blountia kindlei Resser, Coosella DRAINAGE limestone. brevis Besser, Kingstonia ara (Walcott), Kingstonia kindlei Resser, Menomonia avitas (Walcott). Other undescribed These quadrangles lie in the Susquehanna River drainage Distribution. There are only two small tracts of the species have been referred to Blountia, Modocia, Loncho basin, and the principal streams are the Juniata River, Rays- Pleasant Hill limestone in this area one about a mile north­ cephalus, Kingstonia, and Genevievella. Pemphigaspis bullata, town and Frankstown Branches of the Juniata, Clover Creek, east of Henrietta, in the southeast corner of the Hollidaysburg a peculiar and problematic fossil described by Hall. 3 has been Piney Creek, and Plum Creek, in Morrisons Cove, and Great quadrangle, and the other on the high knob about three- found at two localities, at one of which the containing beds Trough Creek, in the Trough Creek Valley. The part of the quarters of a mile northeast of Ganister, in the northwest corner are near the top of the Warrior. quadrangles west of Tussey Mountain is drained by Frankstown of the Huntingdon quadrangle. This fauna is clearly of early Upper Cambrian age. Iden­ Branch; the part east of Tussey Mountain, except a small area Character. The lower part of the Pleasant Hill limestone tical or related species are found in the upper part of the east of Sideling Hill, is drained by Raystown Branch. Rays- is composed of thin-layered argillaceous, sandy, and mica­ JSTolichucky shale and Conasauga formations of the southern town Branch is the largest stream in the area and is remarkable ceous limestone with some calcareous shale, and the upper part Appalachian region; in the Eau Claire sandstone of Wisconsin; for its meandering course. of thick-bedded fine-grained dark-gra}r limestone. On weath­ the Bonneterre dolomite of Missouri; the Cap Mountain lime­ The fall of the larger streams is moderate, but the slope of ering the argillaceous layers turn to clay shale or to greenish stone of Texas, and the Pilgrim limestone and its equivalents the smaller streams heading close to the high escarpments is sandy, micaceous, shaly rock, pieces of which 1 foot square in the western United States. rather steep, even along their lower courses. The range of and smaller are scattered plentifully upon the surface of its grade is shown in the following table: outcrop. Some layers of the limestone have dark oolitic grains and larger rounded dark inclusions that look like pebbles and Amount and rate of fall of principal streams in the Hollidaysburg and Name and definition. The Gatesburg formation was named Huntingdon quadrangles are fossiliferous. Thickness. As delimited the total thickness is about 600 for Gatesburg Ridge, in Centre County, Pa., on which is strik­ Length Total fall Fall Stream (miles) (feet) (feet per mile) feet, of which the lower argillaceous part makes up 400 feet ingly displayed the characteristic mantle of sand and sandstone and the upper pure limestone part 200 feet. boulders derived from the formation by weathering. It includes 85 160 4.6 Age. The following fossils identified from a larger number the Stacy dolomite member at the bottom and the Ore Hill Frankstown Branch ...... -..-_.-__. _ _ 81. 5 340 10.8 of species collected at Pleasant Hill are believed to indicate limestone member in the middle. 19 550 29 the Middle Cambrian age of the Pleasant Hill limestone: Distribution. The Gatesburg crops out west and southwest Crreat Tro u gh Creek ..._____.. _ ..... 18.5 510 28 of Williamsburg, on the Woodbury anticline northeast of Beaverdam Creek (to Altoona,) ..._...... __ 9 190 21 Hyolithes princepsf, AloMstocare sp., Blainia and Olenoides sp. Poplar Run ...... __._...... __.._. ..___.... 5.5 840 62 Martinsburg, near Ore Hill, and in the fault block just west WARRIOR LIMESTONE of Henrietta. The best exposures are on the river bluffs near The average rate of fall shown in the last column fails to Name and definition. The Warrior limestone was named Williamsburg and along the Pennsylvania Railroad east of express a significant feature of the stream beds the diminish­ for Warriorsmark Creek, in the northern part of Huntingdon Birmingham, a few miles north of the Huntingdon quadrangle. ing rate of fall downward. For example, Frankstown Branch County, along which it crops out. The formation occupies the The quartzite layers are best displayed at the Birmingham falls 160 feet in the first 7 miles of its course, which is 23 feet stratigraphic interval between the Pleasant Hill limestone locality. to the mile, 100 feet in the next 9 miles, which is 11 feet to below and the Gatesburg formation above. Character. Exclusive of the Ore Hill limestone member, the mile, and 80 feet in the next 14 miles, which is 6 feet to Distribution. The Warrior limestone crops out in a strip the Gatesburg formation is composed predominantly of thick- the mile. l-£- miles west of Williamsburg, in a small area northwest of bedded, coarsety crystalline dark-bluish dolomite with layers Drab, in the fault block half a mile northwest of Henrietta, of quartzite, which are especially abundant in the upper 1,200 DESCRIPTIVE GEOLOGY and in a triangular area in the southwestern part of the feet. Some light-colored and finer-grained layers of dolomite STRATIGRAPHY Hollidaysburg quadrangle. occur. Oolitic layers and layers full of rounded sand grains Character. The Warrior formation is predominantly fine­ abound. The distinctive characteristic, however, is the quartz­ SYSTEMS REPRESENTED grained dark-gray limestone, in layers 1 foot or less thick, ite in layers 1 to 10 feet thick. The surficial sand, boulders, Except the alluvial deposits along the streams, the rocks commonly separated by shaly partings. A large part is highly and cobblestones resulting from the weathering of these layers that crop out in the Hollidaysburg and Huntingdon quad­ magnesiaii, even dolomite, but the formation includes con­ give the impression that the underlying rocks are sandstone rangles are of Paleozoic age. The total thickness is 23,000 siderable pure limestone, some thin quartzite beds, and layers only. In places the residual sand is as much as 20 feet thick. to 25,000 feet, and all the Paleozoic systems except the full of rounded quartz grains. The following section illus­ The sand grains are from 0.1 to 1 millimeter in diameter. Permian are well represented. trates the various phases: Silicified oolite, abundant near the top of the formation, resembles a mass of millet grains embedded in a sandy matrix. CAMBRIAN SYSTEM : /Section of the Warrior limestone on ffranhstown Branch midway between Williamsburg and Ganister The oolite grains range from 0.5 to 1.25 millimeters in diameter. The rocks of Cambrian age include, in ascending order, the The Gatesburg yields practically no chert, a character by Gatesburg formation. Waynesboro formation, the Pleasant Hill limestone, the Warrior Warrior limestone: which it can be easily distinguished from the Mines dolomite, limestone, and the Gatesburg formation. 22. Not exposed, about______next overlying it. At the top of the formation is a layer of 21. Limestone, bluish, thin bedded; contains trilobites, dolomite full of poorly preserved gastropods belonging mainly WAYNESBORO FORMATION about ______50 20. Dolomite or magnesian limestone, dark, fine grained, to the genus Sinuopea. Name and definition. The Waynesboro formation was about ______300 Thickness. The thickness of the Gatesburg formation is 19. Limestone, gray, full of rounded quartz grains; pro­ named for its exposures at Waynesboro, in. Franklin County. jects prominently like a dike on face of bluff.______10 1,750 feet. Of .this thickness the Ore Hill limestone member It is the oldest exposed formation in these quadrangles, where 18. Not exposed______.. ______50 makes up 100 feet and the Stacy dolomite member, at the it is overlain by the Pleasant Hill limestone. 17. Dolomite or magnesian limestone, blue, sandy ______10 16. Dolomite or magnesian limestone, sandy, cross- bottom, 500 feet. Distribution.- The formation crops out only on the north bedded; weathers to sandstone ______Topographic expression. Owing to the resistant character of half of the low ridge that extends south from a point 1 mile 15. Dolomite or magnesian limestone, with sandy streaks the formation it everywhere forms rather high ridges within and layers 6 inches or less thick______west of Clover Creek, in the southeast quarter of the Holli­ 14. Quartzite, core of dikelike projection on face of bluff the comparatively level limestone valleys. Most of the area of daysburg quadrangle. The rocks along this ridge have been 13. Dolomite or magnesian limestone, sandy______these ridges is forested. thrust up as a wedge between two faults, and the Waynesboro 12. Dolomite or magnesian limestone, some cross-bedded 11. Quartzite r.______Stacy dolomite member. The Stacy dolomite member was is out of its normal relations to the adjacent rocks, except at 10. Dolomite or magnesian limestone ______named for Stacy Knob, 1 mile west of Larke, in the Hunting­ the south edge of its outcrop, where it dips normally south 9. Dolomite or magnesian limestone, with quartzite layers______.. ______don quadrangle. It makes up the lower 500 feet of the under the Pleasant Hill limestone. 8. Dolomite or magnesian limestone, thick bedded______Gatesburg formation and is distinguished by the absence or Character. The part of the Waynesboro that crops out in 7. Not exposed______relative fewness of quartzite beds. this area consists of green and dark shale, some bands of 6. Dolomite or magnesian limestone, blue, thick bedded 5. Not exposed.______There are 110 complete or even good exposures of the Stacy purple shale, thin-bedded fine-grained greenish micaceous 4. Dolomite or magnesian limestone, bluish, thick bed­ member in the area, but a very good idea of its general char­ sandstone, layers of hard quartzite, and layers of quartz con­ ded______10 3. Limestone, argillaceous, siliceous, shaly, with quartz acter can be obtained from the soil, dolomite debris, and glomerate containing abundant pebbles from the size of millet grains __ --- ______.. 20 scattered exposures of the beds on the summit and west side of grains to that of peas. Surficial pieces of porous, highly ferru^- 2. Dolomite, sandy, flaggy ______50 Stacy Knob. ginous sandstone with traces of fossils indicate calcareous sand­ 1. Dolomite or magnesian limestone, dark, fine grained, about. ______..______.._____ ... !!..____ 180 Ore Hill limestone member. The Ore Hill limestone mem­ stone bands from which the calcium carbonate has been 1,251 ber was named for Ore Hill, in the southwestern part of the leached out in weathering. Hollidaysburg quadrangle, where it has been quarried. It lies Thickness. -The conditions of exposure do not permit a The quartzite layers of this section are composed of sub- about at the middle of the upper two-thirds of the Gatesburg close determination of the thickness of the exposed part of this angular to well-rounded translucent quartz grains like those formation, which may not exceed 200 or 300 feet, and, as its so abundant in some of the limestone layers. The grains are 3 Hall, James, Supplementary note on some fossils of the lower beds of the Potsdam sandstone of the upper Mississippi Valley: New York State bottom is not exposed, its full thickness here is unknown. 0.1 to 1 millimeter in diameter; Cab. Nat. Hist. Sixteenth Ann. Kept., p. 221, pi. 5, A, figs. 3-5, 1863. - - 3 formation and is known from Larke to a point 1-J-' miles Missouri Bureau of Mines and Geology in March, 1930. 4 Thickness. The Nittany is about 1,000 feet thick as northwest of the town of Clover Creek, thence northward along This horizon has also been recognized in central Texas and is measured southwest of Roaring Spring, where the rocks are both flanks of the Woodbury anticline about to the latitude of probably present in the lower portion of Chepultepec dolomite vertical and the limits can be determined closely. Larke, and at a number of points on the east limb of the of the southern Appalachian region. Age and correlation. Fossils are scarce in the Nittany, Roaring Springs anticline from Ore Hill southward beyond the being liberated from the dolomite matrix and brought to limits of the Hollidaysburg quadrangle. LARKE DOLOMITE view only in the residual chert. Search in a pile of chert It is best displayed just north of the road half a mile north­ Name and definition. The Larke dolomite is well exposed usually results in the discovery of a few specimens, mostly west of Drab, at a quarry on the same outcrop on the ridge at Larke, 3 miles south of Williamsburg, and the formation gastropods (snail shells), generally so badly preserved as not to 2 miles north of Drab, and at a quarry by the roadside three- was named for that place. It includes the dolomite between be identifiable with certainty. The most common and best quarters of a mile southwest of Ore Hill, where road inetal was the cherty Mines dolomite below and the light-gray and fossil- preserved of these fossils are species of Lecanospira. This obtained for the State highway. iferous Nittany dolomite above. form marks the lower beds of the Beekmantown limestone at The Ore Hill is a thin-bedded bluish to dark-gray, mostly Distribution. The areal distribution of the Larke is the Beekmantown, N. Y.; a horizon near the middle of the Knox fine-grained limestone, with a few coarse-grained layers. It is same as that of the Mines and Gatesburg. The best exposures dolomite in Virginia and Tennessee; the Long view limestone about 100 feet thick. are at Larke, along the railroad just east of Williamsburg, half of Alabama; the Roubidoux formation of Missouri; and a Age and correlation. The only described species are Pelagiella a mile southeast of Williamsburg on the road to Sparr, and on' horizon near the middle of the Ellenburger limestone of Texas. hoytifj Elvinia roemeri, Cheilocephalus buttsi, Burnetia cava, the crossroad just west of the railroad track about a mile south Throughout the geographic range mentioned Lecanospira is and B. pennsylvaniea. Among the described genera are species of Roaring Spring. present in and confined to the lower 1,000 feet or less of the of Irvingelta, Housia, Plethopeltis, and Saratogia. Character. The Larke dolomite is composed mainly of dolomite of Beekmantown age. This same characteristic fossil Two fauna! horizons representing widely separated horizons thick-bedded, coarsely crystalline dark-blue dolomite with a is known through Quebec to Newfoundland and even in the in the middle and late Upper Cambrian appear to be repre­ very little sandstone in thin layers and light-gray chert in Durness limestone of northwestern Scotland and marks a con­ sented in the collections from this member. Elvinia, Burnetia,- thin plates. The lower 50 feet is light gray, fine grained, and tinuous ancient seaway from Scotland to Missouri. Another Irvingella, and Housia are all characteristic of the Franeonia thin bedded or laminated, with siliceous matter in thin laminae gastropod, Roubidouxia umbilicata, characteristic of the Roubi- sandstone of Wisconsin and its equivalents, such as the Da vis that appear as fine raised lines on weathered surfaces. doux formation of Missouri, and known from the same horizon formation of Missouri, the Honey Creek limestone of Oklahoma, Thickness. The total thickness of the Larke is 250 feet. in the southern Appalachians and Texas, has been found in the the lower part of the Wilberns formation of Texas, a portion of Age and correlation. Helicotoma uniangulata, a very widely Nittany. of the Tyrone quadrangle, north of the Huntingdon the Deadwood formation of the Black Hills, and the Dunder- distributed gastropod, diagnostic of the Chepultepec dolomite quadrangle. berg shale of the Eureka district, Nevada, and its equivalents of Alabama, the Gasconade dolomite of Missouri, the Oneota elsewhere in western North America. Elvinia roemeri also dolomite of Wisconsin, and equivalent beds elsewhere in North occurs in the Theresa dolomite of New York. America, .and a species of Finkelnbergia, apparently identical Name and definition.- The Axemann limestone was named Plethopeltis, Saratogia, and Pelagiella hoyli also occur in the with a species common in the Gasconade dolomite of Missouri, for its outcrops about 1 mile east of Axemann, in Centre Hoyt limestone of New York, which some consider to be late occur in the Larke. The type specimen of H. uniangulata was County. As the Axemann is a limestone in the midst of dolo­ Upper Cambrian equivalent to the Jordan and Madison for­ found in the vicinity of Saratoga Springs, N.Y., in chert believed mite, it is very serviceable as a horizon marker. It separates mations of the Upper Mississippi Valley and the Eminence to be derived from cherty beds in the top of the Little Falls the Nittany dolomite below from the Bellefonte dolomite dolomite of Missouri, whereas others make the Hoyt equivalent dolomite. All these formations are overlain by limestone above. to a portion of the Franconia. The close association of these or dolomite of Beekmantown age, which, except in Wisconsin, Distribution. The Axemann limestone crops out in a sinu­ forms with fossils of early Franconia age in the Ore Hill lime­ corresponds to a portion of the Nittany dolomite, which overlies ous belt marked by quarries from a point near Barbara, in the stone member lends support to this view. On the ground of the Larke. The Larke is therefore correlated with the Gas­ northeastern part of the Hollidaysburg quadrangle, to a point stratigraphic relations the Gatesburg is also tentatively correlated conade, Chepultepec, Oneota, and upper part of Little Falls about 1 mile south of Roaring Spring. Another strip offset with the Conococheague limestone of Cumberland Valley, Pa., dolomites. by the Henrietta faults extends from Shelley town, in the and the Copper Ridge dolomite of Virginia, Tennessee, and HIATUS BETWEEN LARKE DOLOMITE AND NITTANY DOLOMITE Huntingdon quadrangle, 4 miles south of Williamsburg, to Alabama. the south boundary of the Hollidaysburg quadrangle. At Bellefonte, in Centre County, the Mines dolomite is OKUOVICIAN SYSTEM About 1 mile south-southwest of Roaring Spring the succeeded above by the Stonehenge limestone, which is 662_ Axemann limestone can be distinguished between the Nittany Iii these quadrangles the rocks of Ordovician age consist feet thick. Throughout most if not all of these quadrangles, and Bellefonte dolomites, but it could not be traced farther predominantly of dolomite and limestone but end above with a however, the Stonehenge limestone is absent and the Larke south, notwithstanding the fact that at one place there is a thick sbale formation. They include the following formations, dolomite is unconformably overlain by the Nittany dolomite. continuous exposure of 200 or 300 feet of dolomite apparently named in ascending order: Mines dolomite, Larke dolomite, NITTANY DOLOMITE including the Axemann horizon. It likewise appears to be Stonehenge limestone (?), Nittany dolomite, Axemann limestone, absent in a belt stretching from a point less than half a mile Bellefonte dolomite, Carlim, Lowville, Rodman, and Trenton Name and definition. The Nittany dolomite was named north of Shelley town to the north edge of the Huntingdon limestones, Reedsville shale, Oswego sandstone, and Juniata for its exposures in the vicinity of Nittany Furnace, near quadrangle, but at Mount Etna, 2i miles due north of Cove formation in all about 5,900 feet thick. Bellefonte, in Centre County. In this area it extends from the top of the Larke dolomite to the bottom of the Axemann Forge, it is present and has its usual thickness and character. B1SBKMAXTOWK GROUP limestone, the intervening Stonehenge limestone not being The best exposures of the Axemann are in the broad outcrop The Beekmantown group of the Champlain Valley is repre­ certainly identified. where it swings around the south end of the Scotch Valley sented in the Hollidaysburg and Huntingdon quadrangles by Distribution. Beginning at the fault in Bloom field Town­ syncline 1-J- miles southwest of Curry ville and at Shelleytown, the Mines dolomite, the Larke dolomite, the Nittany dolomite, ship, near the southwest corner of the Hollidaysburg quad­ where the section given below is exposed. the Axemann limestone, and the Bellefonte dolomite. rangle, the Nittany dolomite crops out in a broad zigzag belt Character. The Axemann consists mainly of limestone but contains & few thin layers of dolomite. The limestone is thin, MINES DOLOMITE running to the north line of the Huntingdon quadrangle 3 miles north of Williamsburg. There are also two small areas bedded and dark bluish gray, and its several layers range in Name and definition. The Mines dolomite was named for at the quadrangle boundary north of Ganister. The best texture from coarse grained to nongranular. Some layers con­ the town of Mines, 5 miles southwest of Williaeisburg. Its exposure of the Nittany is along the south bank of Franks- tain small rounded pebbles of black limestone and others flat outcrop, marked by abundant chert, passes about a quarter of town Branch 1 mile northeast of Williamsburg, where nearly pebbles of considerable size. The limestone weathers to a a mile east of Mines. It extends from the top of the Gates- every foot is visible. In these quadrangles the Stonehenge, smooth bluish surface easily distinguishable from the gray- burg to a bed of light-gray fine-grained siliceous dolomite with which underlies the Nittany farther east, is not certainly kilown, weathering, sandy-looking dolomite above and below it. Fos­ brachiopods (Lingula) that crops out on the east brow of the but it may be represented by a few feet of dark, compact lime­ sils are common in the layers that have the black pebbles and ridge between the eastern two of the three roads leading south­ stone at the base of Nittany exposed about four-fifths of a mile are present throughout the formation. Below is a detailed ward from Williamsburg. southeast of Ore Hill. About 10 feet of thin-bedded dolomite section of the limestone measured at Shelleytown : ,c Distribution. The Mines dolomite has the same distribution is exposed immediately beneath this limestone at that point. Section of the Axemann limestone at Shelleytoton as the Gatesburg formation. It is best displayed just south of Character. The Nittany is all dolomite, mostly light gray Bellefonte dolomite. irt. in. Williamsburg on the crest of the ridge above mentioned. or bluish gray, fine grained, and in layers as much as 2 feet 48. Dolomite ______5 Character. The dolomite of the Mines resembles closely in thick. (See pi. 10.) It has a few layers of coarse-grained Axemann limestone: - - .^= outward appearance that of the Gatesburg formation. How­ 47. Limestone, thin bedded, dark, fine-grained, dark-gray dolomite and a few with quartz grains. The banded; contains fossils- __ .___-____ 1' ______10 ever, the Mines yields abundant chert and has no sandstone, bottom 50 to 100 feet, as exposed north of Williamsburg, is 46. Dolomite or magnesian limestone ______1 3 whereas exactly the reverse is true of the Gatesburg. Much of 45. Limestone, dark "blue, granular ______.__ 6 thin bedded, argillaceous, and slightly ferruginous, weathering 44. Not exposed- _ __ --.._..--_.______the Mines chert is very rough or scoriaceous; some of it is to clay with thin rusty slabs of dolomite. Much dense resid­ 43. Limestone ?____. _':___.. _J-__. ______10 oolitic; most of it is light gray but is made very dark by ual chert in pieces, the largest 6 feet in diameter, is scattered j '.. '; ,42. Dolomite_____- -'---_----___-_-__-_,.__-______characteristic black oolite grains. The pieces of chert are of 41. Not exposed ______over the surface underlain by the Nittany. Chert full of 40. Limestone, blue ______all sizes up to a foot or more in diameter. Many pieces consist rhombohedral cavities from which crystals of calcite or dolo­ 39. Limestone, dark, granular, thin bedded; of silicified specimens of Cryptozoon, the individuals ranging weathers blue ; contains fossils ______15 mite have been dissolved out is common. A little of the chert 38. Partly exposed ; shows blue limestone layers and from 1 inch to more than 1 foot in diameter. These chertified is oolitic, but in contrast to the oolitic chert of the Mines, the at least one thin layer of dolomite. ______25 specimens of Cryptozoon and the black oolite grains are con­ oolitic grains are generally white in a black matrix. There 37. Limestone, dark, coarse grained; contains fos- fined to the Mines dolomite, occur everywhere on its outcrop, sils______:_-_-.. ______8 is, however, but little chert in the dolomite itself. In a com­ 36. Not exposed __ .______'______3 and serve to identify it with certainty. pletely exposed section of about 1,000 feet along the river 35. Limestone, dark, granular, partly exposed _____ 4 Thickness. The Mines is about 250 feet thick. 34. Not exposed ______. __ (?) bank about 1 mile northeast of Williamsburg only two beds, 33. Dolomite, light blue, fine grained, shaly __ __ 1 Age and correlation. At the bottom of the Mines on the one 5 feet and the other 1 foot thick, were seen. Elsewhere 32. Limestone, coarse grained; crinoidal joints point of the spur just south of Williamsburg is a layer of its only a few thin layers of oolitic chert and scattered plates, abundatit-_-______-.. ______4 characteristic dolomite about 2 feet thick crowded with the 31. Not exposed ______.._..______4 stringers, and nodules were observed. On the broad, flat spur 30. Limestone, dark, line grained ______1 remains of gastropods of the genus Sinuopea. These are 1 mile southwest of Clover Creek post office spheroidal masses 29. Dolomite, light bluish, fine grained ______1 hardly if at all distinguishable from S. vera and S. planibasalis 28. Limestone, dark blue, mostly coarse grained. __ 12 of chert, the largest 8 Inches in diameter, attract attention. 27. Limestone, dove-colored, glassy texture __ _. _ 1 of the cherty dolomite which in the past has been assigned These chert balls may be of organic origin, being perhaps 26. Dolomite ______\ to the lower part of the Gasconade dolomite of Missouri but another form of Cryplozoon, either C. steeli or C. minnesotense: 25. Limestone, daik, granular, thin bedded ______8 which is treated by H. S. McQueen as a separate unit, under 24. Dolomite.- ______2 4 The Missouri Geological Survey now (1943) considers the Van Buren to 23. Limestone, dark blue, line grained ______. 1 the name Van Buren formation, in a report issued by the be the basal member of the Gasconade dolomite. 22. Dolomite, light, fine grained, thick bedded ____ 6 Hollidaysbui-g-Huntingdon Ft. in. 21. Limestone, dark, coarse grained______2 6 Nittany. The only well preserved ones seem to be Hormotonea the Josephine quarry, 1-|- miles north of the Clover Greek 20. Not exposed______.___..______2 gradient. Ceratopea was found a short distance west of Covedale quarry, it appears to be about 100 feet; at Carlim, about 100 19. Limestone, dark blue, fine grained, thin bedded 15 in the Huntingdon quadrangle. feet; at the Blair quarries, 2 miles north of Carlim, beyond 18. Dolomite______..______1 17. Limestone, like No. 19__.______20 The most significant of the fossils, Ceratopea, is the operculum the quadrangle line, 200 feet; at the St. Clair quarry, at 16. Limestone, shaly______3 of a gastropod, although the shell to which it belongs has not Ganister, 175 feet; and at Roaring Spring the Carlim and 15. Limestone, dark, coarsegrained_:______. 1 6 14. Dolomite______2 yet been discovered. Several species of the genus have been Lowville limestones together have a thickness of about 430 13. Limestone, dark, thick bedded._...______._____ 2 6 differentiated, all apparently confined to that part of the Beek­ feet, of which about 250 feet is believed to belong to the 12. Dolomite-______-__.__-_____--____-__---..______1 mantown group younger than the Nittany dolomite. They are Carlim. The average thickness is about 180 feet. 11. Limestone, dark, thick bedded____..______..__ 7 10. Dolomite, light and dark gray, fine grained..... 1 6 especially abundant in the Cotter dolomite of Arkansas, where Lemont argillaceous limestone member. The upper 30 to 40 9. Limestone, dark, granular, thin bedded ____., 6 species of other genera found here are associated with them. feet of the Carlim limestone in Blair and Huntingdon Counties 8. Dolomite, banded with siliceous layers._..__..___ 4 7. Limestone, dark, granular, thin bedded _.._____ 5 The Ceratopea zone has been traced from Pennsylvania is highly siliceous and argillaceous, weathering a dirty white 6. Dolomite ___.__...._____.____..______1 3 through Virginia and Tennessee into Alabama, where it is or gray or yellowish color and appearing quite different from 5. Limestone, dark, granular, thin bedded ______6 included in the Newala limestone. The discovery, since the the rest of the Carlim. Some layers are reported to contain as 4. Not exposed-,._____...__...______..__...... 2 3. Dolomite______.-_....-_-..______2 above was written, in limestone of Bellefonte age in Virginia, much as 25 per cent of insoluble matter. On account of this 2. Not exposed__.______..._..-_-______...... 2 of such characteristic Fort Cassin fossils as Plethospira cassini, difference in character these beds have been set off as a distinct 1. Limestone or dolomite, shaly______.._..______1 Nittany dolomite. Fusispira obesa, Calaurops lituiformis and several species of member, to which the name Lemont was given, because of 203 6 large coiled cephalopods, which are especially characteristic of their exposure at Lemont, near State College in Centre Thickness. According to the preceding section, the Axemann the limestone in the Fort Cassin region of Vermont, proves County. Throughout central Pennsylvania the Lemont mem­ is 203 feet thick. This thickness appears to be the maximum. conclusively the Fort Cassin age of a considerable part, at least, ber is present wherever the Carlim is present. It is well known Its upper and lower limits can not everywhere be accurately of the Bellefonte. to quarrymen, as it is fit only for road metal or ballast and is

determined, but most observations seem to indicate a thickness HIATUS BETWEEN BELLEFONTE DOLOMITE AND CARLIM LIMESTONE an impediment to quarrying the better rock (Lowville and of about 150 feet. Carlim) above and beneath it. In some quarries it is left So far as known there is a hiatus between the Bellefonte Fossils and correlation. Fossils are fairly abundant in the standing as a projecting rib owing to the removal of the good dolomite and the overlying Carlim limestone. A time interval Axemann limestone. The species are largely undescribed, but rock on both sides of it. (See Atlas of Pennsylvania No. 96, of great length may be unrepresented by sediments in central some have been identified either specifically or generically, Tyrone Quadrangle, Plate 7A.) Pennsylvania. including one species of brachiopod, nine species of gastropods, Age and correlation. The Lemont member of the Carlim is and seven species of trilobites. CARLIM LIMESTOK.E moderately fossiliferous in these quadrangles and more so at Of the trilobites two species are identical with or very close Name. The Carlim limestone was named for its exposures Lemont, Centre County, and at Naginey, Mifilin County. relatives of species that occur in the fossiliferous beds at Fort in the Carlim quarry in the northwestern part of the Hunting­ The lower part of the Carlim is less fossiliferous. TwentyT Cassin, Vt, somewhat above the middle of the Beekinantown don quadrangle. It overlies the Bellefonte dolomite and eight species from the Carlim have been identified, the most limestone. Most of the gastropods likewise are Beekmantown underlies the Lowville limestone. The exact bottom of the useful of which for correlation are Mimella vulgaris and forms known from Newfoundland to Alabama, where they occur Carlim is somewhat difficult to locate in the field owing to Opikina champlainensis, with which Maclurites magnus is in the lower part of the Newala limestone and beneath the Cera- the mixture of layers of sparsely fossiliferous blue limestone associated at Lemont and Naginey. These forms characterize topea zone described under the Bellefonte dolomite. Maclurites with layers of dolomite forming a transition zone from the limestone in the middle Chazy at Crown Point, N. Y., on affinis is especially notable for the persistence of its occurrence Bellefonte to the Carlim. The lowest fossiliferous limestone Lake Champlain, and Haclurites magnus is abundant in and at this general horizon throughout the Appalachian Valley, layers are taken as the bottom of the Carlim. Such appar­ characteristic of the Lenoir limestone of Tennessee and Ala­ and it occurs also in the limestone at Fort Cassin. It seems, ently gradational phenomena are probably the result of mixing bama. Another species, Ancistrorhyncha (Protorhynchd) cf. A. therefore, that the Axemann may occupy a horizon substan­ of residual material from the rocks of the earlier formation ridleyana, is a guide fossil of the Ridley limestone of the Stones tially equivalent to the lower part of the Newala limestone of with the first deposited material of the succeeding formation. River group of the Nashville Basin of Tennessee. The Lemont Alabama and beneath the horizon of the Cotter dolomite The Carlim limestone is of especial interest because of its is therefore correlated with the Chazy beds at Crown Point, of Arkansas, in which Ceratopea is very abundant. Owing to large utilization as flux in the smelting furnaces at Pittsburgh. the Lenoir limestone of the southern Appalachian region, and the common elements in the faunas of the Axemann limestone Distribution. The Carlim limestone crops out in a narrow the Ridley limestone of middle Tennessee. Two other fossils and the limestone at Fort Cassin the two horizons have been band along the west foot of Tussey Mountain to Henrietta, found in the lower part of the Carlim and somewhat doubtfully tentatively correlated, but Ulrich seems inclined at present to where its outcrop is offset westward by the Henrietta faults. identified Salterella billingsi and Helicotoma subquadrata correlate the Axemann limestone with the Jefferson City dolo­ Farther west, beginning at a point on the Henrietta fault suggest the correlation of the lower part of the Carlim with the mite of Missouri, which lies below the Cotter dolomite ( Ceralopea 1 mile north of Ganister, its outcrop follows the southeast base Murfreesboro limestone, the basal formation of the Stones River zone) of that region and thus appears to hold the same strati- of the Lock-Dunning Mountain ridge nearly across the quad­ group of middle Tennessee. graphic position as the Axemann. rangle, passing through Martinsburg and Roaring Spring. HIATUS BETWEEN CARLIM AND LOWVILLE LIMESTONE Character. The lithologic character of the Carlim limestone BELLEFOXTE DOLOMITE is indicated in the following section, which is typical for the The Lenoir limestone of eastern Tennessee is of about the Name and definition. The Bellefonte dolomite was named region. same age (middle Chazy) as the Lemont member of the Carlim, for Bellefonte, Centre County, a large part of the town being and the typical Bays sandstone of Tennesse is regarded as of Section of Lowville and Carlim limestones at Clover Creek quarry situated upon its outcrop. It includes all the dolomite of about the same age as the Lowville limestone, which overlies these quadrangles above the Axemann limestone and below Feet the Lemont member. The Lenoir and the typical Bays, how­ Trenton limestone______500± ever, are separated by a considerable thickness of intervening the Carlim limestone. Hodman limestone: Distribution. There is a very small area in the northwest Limestone, thin bedded, dark gray, coarsely gran­ rocks, none of which are represented in Pennsylvania. It ular or crinoidal; contains clayey impurity, unfit thus appears that in the Hollidaysburg-Huntingdon region corner of the Huntingdon quadrangle; a long zigzag belt for chemical uses______30 extending from Ganister to a point near Baker Summit, near Lowville limestone: there exists between the Lemont and the Lowville an uncon­ the south line of the Hollidaysburg quadrangle, where its out­ Limestone, thick to thin bedded (see pi. 11), dark, formity represented by several thousand feet of beds in eastern largely nongranular, conchoidal fracture, some Tennessee. Notwithstanding this great hiatus, however, there crop is faulted out; and a belt extending from Williamsburg very finely granular; weathers with white crust, to the vicinity of Henrietta. The best exposure is along very low in impurities; contains Tetradium cellu- is no discordance of bedding nor any irregularities of contact losum, Cryptophragmus antiquatus, &treptelasma between the Lemont member of the Carlim limestone and the Frankstown Branch about 1 mile northeast of Williamsburg. profundum; about______140 Character. Nearly all of the Bellefonte is dark fine-grained Carlim limestone: = Lowville, as shown in Plate 12. Lemont limestone member: thin to thick bedded dolomite. There are a few light-gray beds BLACK RIVER GROUP 7. Limestone, dark, fine grained, argillaceous, and a little dove-colored nongranular limestone. A consider­ siliceous, pyritiferous, fossiliferous; has shale The Black River group in this area is divided into two able thickness of light-gray fine-grained rock in the upper part partings, sun cracks and wave marks; rejected for flux--___.______40 formations the Lowville limestone below and the Rodman of the Bellefonte, effervescing freely in acid and probably low 6. Limestone, dark, nongranular, highly fossilif­ limestone above. in magnesia, is exposed on the railroad opposite the mouth of erous ______10 Beds beneath Lemont member: LOWVILLE LIMESTONE Clover Creek. In one section, through 200 feet of beds that 5. Limestone, dark, thick bedded, in large part are apparently in the upper half of the Bellefonte, the dolomite finely crystalline; some nongranular like No. Name and definition. The Lowville limestone was named is blue and gray with thin layers of dark, apparently carbon­ 6, some earthy layers (see pi. 12) ___. ___ 150 for its exposure in the village of Lowville, Lewis County, N. YJ. 4. Dolomite _---___._____ .______2 aceous shale. 3. Limestone ______2 In these quadrangles it overlies the Carlim limestone and under­ Although prevailingly dark internally, the rock weathers 2. Dolomite ______.___ 2 lies the Rodman limestone. Like the Carlim it is commercially white with a mere chalky film, especially near the top of the 1. Limestone, banded______:____..______2 valuable as a source of flux. 203 Distribution. The Lowville limestone has the same distri­ formation, which gives the Bellefonte a rather distinct aspect Bellefonte dolomite: by which it can generally be easily distinguished from the Dolomite, dark, fine grained; tends to con­ bution as the Carlim limestone. It is exposed in all the overlying Carlim limestone. Throughout the upper 800 feet choidal fracture; weathers with filmy white quarries of the Williamsburg district and can easily be iden­ crust. or more exposed along the river northeast of Williamsburg are tified by its position between the impure, worthless beds of the thin cherty layers here and there in the mass, much of the The main body of the Carlim limestone is dominantly dark Lemont member of the Carlim limestone below and the Rod­ chert being black and in the form of nodules, less in thin bluish gray, finely crystalline, and in layers 1 to 2 feet thick. man limestone above. plates or irregular stringers. The surfaces underlain by the At the bottom, are a few feet to 20 feet of alternating limestone Character. The Lowville is a dark, mostly compact lime­ Bellefonte dolomite are in places strewn with chert in scoria- and dolomite layers. The limestone of the basal layers is stone and has a tendency to conchoidal fracture. (See.pl. 11,) ceous slabs and large boulders. In the lower 200 feet quartz light or dark gray and fine grained or compact. At Carlim Here and there is a layer of fine-grained dark rock such as grains are fairly plentiful. some of these limestone layers are sun cracked and ripple occurs in the Carlim limestone. At or near the bottom of the Thickness. The Bellefonte is about 1,000 feet thick on marked. Lowville is a 5-foot bed crowded with fucoids (fossil seaweeds). Halter Creek south of Roaring Spring, where its limits are The chemical character of the Carlim is indicated by the fact (See pi. 13.) On weathering these fucoids are dissolved out, well defined and where, the layers being vertical, accurate that all cf it except the Lemont member is used for flux. The leaving the rock honeycombed. The rock is of high purity, measurement is possible. It is about 1,250 feet thick east of average composition at one quarry is silica and alumina 4.75, probably purer than most of the Carlim limestone, so that it is Williamsburg. magnesia 4.5, phosphorus 0.08-1, sulphur 0.04, calcium car­ much sought for in quarrying. No analyses from this region Age and correlation. Fossils are even scarcer in the Belle­ bonate to make 100 per cent 90.6-90.63. are available, but in Centre County, where it is the main fonte than in the Nittany dolomite. A few were found at Thickness. The thickness of the Carlim ranges from 100 to quarry bed, many analyses show it to contain generally less three localities, at each place in residual chert, as in the 200 feet. At the Clover Creek quarry it is 208 feet thick; at than 2-^ per cent of insoluble matter. The compact rock is 5

seamed with minute veins and spotted with inclusions of calcite, pieces that are characteristic of the Trenton of this region. Its OSWEGO SANDSTONE owing to which it is sometimes called "calico rock." outcrop can usually be detected through the abundance of Name and definition. The Oswego sandstone was named Thickness. The thickness of the Lowville is 140 to 180 these small blocks scattered upon the surface. The rock for its exposures at Oswego, N. Y. It was called Oneida con­ feet. weathers invariably with a grayish exterior that contrasts glomerate by the Second Geological Survey of Pennsylvania Age and correlation.---The Lowville in this region is fairly strongly with the black interior. The layers generally seem in the mistaken belief that it is the same as the Oneida con­ fossiliferous. Among the 23 forms that have been identified to be in close contact and without conspicuous shaly partings. glomerate of central New York and was later called "Bald are Tetradium cellulosum and C'ryptophragmus antiquatus The quantity of impurities is so great that the rock is unfit for Eagle conglomerate" by Grabau. In these quadrangles it (Bealricea aracilis), which are common in the Lowville lime­ use as flux or lime, and it is not utilized for any purpose. overlies the Reedsville shale and underlies the Juniata stone or its equivalents from Canada to Alabama. They Thickness. Fully reliable measurements of the thickness of formation. occur together also in the upper part of the Ghickamauga lime­ the Trenton are not obtainable in this region, but estimates Distribution. The Oswego sandstone succeeds, with perfect stone in the vicinity of Birmingham, Ala., and indicate that the based on the dip and the width of outcrop give about 350 feet accordance of bedding, the heavy siliceous and fossiliferous Lowville is represented in the Chickamauga. at the east base of Dunning Mountain and 500 feet at the west ( Orthorhynchula) beds included in the top of the Reedsville base of Tussey Mountain, showing that the thickness increases shale. (See pi. 14.) It crops out along the west side of RODMAW I/IMESTO^E eastward. Tussey Mountain and the east side of Lock and Dunning Name and definition. The Hodman limestone was named Age and correlation. In this region the Trenton is not a Mountains, being marked by a distinct bench on the slopes of for its exposures at Rodman, 1 mile north of Roaring Spring. highly fossiliferous formation, as it is in New York, but 19 the ridges near the crest. It is an impure limestone of a highly characteristic aspect and species have been collected from it, including such characteristic Character. The Oswego is fairly thick bedded, fine grained, occupies the space between the thick-bedded Lowville below Trenton species as ^Dalmanella rogata," Dinorthis pectinella, and steely blue-gray on fresh fracture and is speckled with and the Trenton limestone above. Hesperorthis tricenaria, Parastrophina hemiplicata, Rhyncho- iron rust as if from the decomposition of iron pyrites. Many Distribution. The Rodman has the same areal distribution trema. increbescens, Sinuites cancellatus, Spyroceras bilineatum, of the layers are delicately cross-laminated. At Bellefonte, in as the Lowville, at the top of which it crops out throughout Ceraurus pleurexanthemus, Cryptolithus tessellatus, Brongniarlia Centre County, the Oswego includes layers of coarse conglom­ these quadrangles. It is exposed at the top of every quarry in (Homalonotus) trentonensis, Isotelus gigas, and Tlialeops ovatus. erate, but in this region pebbles are scarce; only a few small the region and marks the top of the quarry rock, neither it Besides these are a few species in the base of the Trenton ones were seen on the spurs southeast of Cove Forge. It nor any bed above it being quarried. or in the top of the underlying Rodman limestone that are includes a few beds of greenish and red sandy shale, some of Character. The Rodman limestone is dark, thin bedded, rare in American Ordovician faunas. Brongniartia trentonensis them 5 feet thick. A layer of red shale in the base is exposed coarsely crystalline, and highly argillaceous or siliceous. It has been found only in central Pennsylvania, where it occurs in the railroad cut 1 mile southeast of Tyrone, about 14 miles weathers with a dirty-gray or earth-colored and rough surface. about 60 to 75 feet above the bottom of the Trenton. As this northeast of Altoona. The roughness is due to the coarse grain and the presence of species does not occur in the typical Trenton of New York the In Pennsylvania the Oswego may be of sand flat or fresh crinoid plates and fragments of other fossils. The highly beds carrying it in central Pennsylvania may be somewhat older water origin. The absence of fossils is one reason for this belief. characteristic weathered surface and the fact that it marks the than the basal beds of the New York Trenton. Thickness. The thickness of the Oswego, as nearly as it top of the quarry rock make its recognition easy. It has been can be determined, is 800 feet. REEDSVIIJLE SHAMS recognized in the Bellefonte district also and is no doubt per­ Age and correlation. In New York the Oswego sandstone sistent throughout the Nittany Valley. Name and definition. The Reedsville shale was named for lies above the Lorraine group and below the Queenston shale. Age and correlation. The Rodman is abundantly fossilif­ Reedsville, Pa., near which is a fairly good exposure of the The upper half or so of the Lorraine group (Pulaski shale) is erous, but only in a few localities are well-preserved specimens formation. It extends from the top of the Trenton to the base regarded by Foerste and Ulrich as being equivalent to the at all plentiful. One such place is Rodman, the type locality. of the Oswego sandstone. Fairview formation of the Maysville group of the Cincinnati Among the 43 recognized species the most interesting is the Distribution. The Reedsville shale crops out in a belt half region, Ohio. The Juniata formation, which overlies the "ball eystid" Echinosphaeriles, an ovoid form, with the largest a mile wide along the west flank of Tussey Mountain, where Oswego in Pennsylvania, is correlated with the Queenston diameter 2 inches, related to the modern sea urchins and sea it dips east, and in another belt along the east side of the shale of New York. Further, the Juniata and Queenston are lilies. The Rodman fauna shows sufficiently close relationship Dunning-Lock Mountain ridge, where it dips west. correlated with the Richmond group at Cincinnati, which over­ with that of the JZchinosphaeriles-beairing bed of the Chambers- Character. The Reedsville has at bottom a stratum of lies the Maysville. A few fossils reported by Ulrich from the burg limestone of Pennsylvania as described in the Mercers- black shale, 40 feet or less thick, which includes thin layers basal part of the typical Oswego of New York would indicate burg-Chambersburg folio (No. 170, section, p. 8, column 1) to of black limestone, showing a gradual passage from the Tren­ an upper Fairview and lower McMillan age for that part, and warrant the tentative correlation of the Rodman with that zone ton to the Reedsville. Above the black shale is a considerable it seems most probable that the remaining (upper) part of the of the Chambersburg, which Ulrich has determined to be of body of olive-green shale, much of which is minutely jointed, Oswego corresponds to the upper McMillan part of the upper Black River age. Echinosphaerites also occurs in the so that it weathers out into small prisms, the smallest of which Maysville. Baltic Sea region of Europe in beds regarded as of Black River are the size of shoe pegs. Above the olive-green shale lies JUNIATA FORMATION age. The Rodman fauna is a distinctly upper Black River several hundred feet of dark shale with many sandy and Name and definition. The Juniata formation was named fauna, somewhat closely related to that occurring in the Decorah highly fossiliferous limestone bands 1 foot or less thick. The for the 3 uniata River, along which it is in places well exposed. shale of Iowa and Minnesota. Of related interest is Auloporaf top stratum of the formation, in immediate contact with the It includes all the red shale and sandstone between the under­ trentonensis^ of the Rodman, which is the only species of the overlying Oswego sandstone, is a thick-bedded siliceous, fossil­ lying Oswego sandstone and the overlying Tuscarora quartzite. genus so far reported from beds as old as Middle Ordovician iferous rock 50 feet thick. (See pi. 14.) This bed, called the Distribution. The Juniata crops out on the west side of and which also occurs in the Decorah shale of Minnesota. Orthorhynchula zone from the rather abundant occurrence in Tussey Mountain and on the east side of the Lock-Dunning Other fossils of the Rodman important for correlation are it of Orthorhynchula llnneyi, a distinctive fossil, is persistent Mountain ridge, on both ridges just below the crest. Its out­ Plectoceras undalus and Gonioceras a.ncej>s, which occur in the in both lithologic and paleontologic character southward to crop is marked by a depression between the crest of the ridge Watertowii limestone of the Black River group of New York, northern Tennessee and is thus a. very important horizon made by the Tuscarora quartzite and the bench on the sides of the first being confined to that zone so far as reported. The marker. the ridges made by the Oswego sandstone. There are no good Rodman is tentatively correlated with the Watertown. The basal black shale is well displayed in the old ore bank exposures of the Juniata in the Hollidaysburg and Huntingdon at Henrietta, in the highway southeast of the point of Loop IirATUS BETWEEN RODMAN AND TRE5TON LIMESTONES quadrangles, although its presence beneath the areas of its out­ and Lock Mountains about 2 miles north of Martinsburg, and crop can everywhere be detected by the red soil and de'bris and In the Chambersburg region about 600 feet of fossiliferous along the east base of Dunning Mountain, where pits have by an exposed bed of red shale or red sandstone here and limestone, the Chauibersburg limestone as now defined, which been dug into it in search of coal. The olive-green shale is there. occupies a position apparently intermediate between the Black exhibited at Martinsburg and along the highway east of Short Character. The Juniata formation is composed almost River and Trenton limestones of New York, intervenes between Mountain from McKee Gap to Dry Gap. In fact, debris of wholly of red or brown shale and sandstone. The sandstone the "Echinosphaerites zone referred to above and the base of the this shale is more or less in evidence everywhere on the out­ is fine grained and carries flakes of rnica. Many of its layers Martinsburg shale of that region, the lower part of which cor­ crop of the formation. The dark shale with limestone bands are delicately cross laminated. The shale is not fissile but responds to the Trenton limestone. In the Hollidaysburg- forming the upper part of the formation is best exposed in the lumpy and would be more properly designated a mudrock. Huntingdon region the Trenton limestone immediately succeeds cut of the Pennsylvania Railroad between Point View and It is slightly micaceous and appears to be sandy. The forma­ the Rodman limestone, leaving a stratigraphie gap caused by the Franklin Forge. tion is not well enough exposed in this region to permit an absence of the intermediate beds of the Chambersburg region, Thickness. The total thickness of the Reedsville is 1,000 estimate of the proportions of shale and sandstone, but a good provided of course that the Rodman is correctly correlated with feet. , exposure in the gap through Bald Eagle Mountain just east of the Echinosphaerites zone. Of the 42 species of fossils from the Reedsville that have Tyrone, about 12 miles north of Point View, shows a great been identified, Diplograptus foliaceus vespertinus, Climaco- TRENTON LIMESTONE preponderance of red sandstone. The formation is nonfossil- graptus aff. C. typicalis, and Triarthrus becki occur in the iferous throughout. Name and definition. The name Trenton is an old one and basal black shale and suggest that it is of Utica age. Aspido- Thickness. In this region the average thickness of the was taken from Trenton Falls, on West Canada. Creek, in pora newberryi, Hallopora sigillaroides, Dalmanella multisecta, Juniata formation is 850 feet. Herkimer County, N. Y. In these quadrangles the Trenton Lingula nic/clesi, Orthorhynchula linneyi, Plectorthis fissicosta, Age and correlation. The Juniata in this region is destitute is bounded below by the Rodman limestone and above by a Strophomena hallie, Zygospira cincinnatiensis, Byssonychia of fossils and therefore contains no internal evidence of its bed of black shale in the bottom of the Reedsville shale. radiata?, Lyrodesma poststriatum, Plerinea demissa, and geologic age. It is known, however, to be of the same age as Distribution. The Trenton has the same general surface several more pelecypods correlate the Reedsville with the the Queenston shale, which is exposed in Niagara Gorge in distribution.as the Carlim and Lowville at the west base of Lorraine group of New York, the Eden and Maysville groups New York and Canada. The red rock was reached at a depth Tussey Mountain on the east and along the east base of the of southwestern Ohio, and the upper two-thirds of the Martins­ of about 5,500 feet in a deep well near Bradford, Pa., about Lock-Dunning Mountain ridge on the west. It crops out just burg shale in other belts of the Appalachian Valley. Ortho­ midway between central Pennsylvania and Niagara Falls. east of the quarries on Clover Creek and at Carlim and just rhynchula linneyi, Lingula nicMesi, Byssonychia radiataf, and Northwest of Niagara Falls through Ontario fossils appear in west of the quarries on Piney Creek and at Roaring Spring. several other pelecypods form a persistent assemblage in the the Queenston that prove it to be of the same age as the highly Character. The Trenton limestone is thin bedded, dark to upper 50 feet of the Reedsville or the Martinsburg shale from fossiliferous Richmond group of the Cincinnati region of Ohio black, nongranular or very fine grained, somewhat argillaceous central Pennsylvania, to central east Tennessee, where this zone and Indiana. and siliceous, and moderately fossiliferous. The thinnest has been recognized on the northwest side of Clinch Mountain layers are half an inch thick, and most of them are probably near the latitude of Morristown. The zone can be surely SILURIAN SYSTEM less than 6 inches thick. At some points exposed layers are identified in every belt of outcrop of the Martinsburg or The Silurian system includes the Tuscarora quartzite, cut by a multitude of cleavage or joint planes perpendicular Reedsville along the northwest side of the valley within the Clinton formation, McKenzie formation, Bloomsburg redbeds, to the bedding, which divide the layers into small blocky limits defined and is called the Orlhorhynchula zone. Wills Creek shale, and Tonoloway limestone. Hollidaysbnrg-Haiitingdon 6

TTJSCABOBA QTTABTZITE Feet burg ore bed. It is generally a highly siliceous, hard, coarse­ feet in middle; layer of "red" (keel) 2 inches Name and definition. The Tuscarora quartzite was named thick reported near middle; "Middle Clin­ grained sandstone 8 to 10 feet thick, yielding an abundance of for Tuscarora Mountain, Pa., a ridge made by an outcrop of ton shales "of White_-______615 large boulders. Locally it is highly ferruginous, weathers 9. Sandstone, hard, fine grained, grayish to the formation. It overlies the Juniata formation and under­ greenish, medium thick bedded______. 40 rather soft and spongy, and is fossiliferous and probably cal­ lies the Clinton formation. It is of special interest as the 8. Sandstone, ferruginous, blocky, yields red careous. It persists along the east base of Tussey Mountain, source of silica or ganister for the manufacture of silica brick sandstone d<5bris, Levant ore bed; "Iron where its outcrop is marked by a hogback or series of low sandstone" and "block ore" of White Nos. and is thus the basis of a large industry in Blair and Hunting­ 5 to 7 of railroad section below______1 knolls, and is especially well displayed around the detached don Counties. 7. Ore, oolitic, fine grained, local; degenerates to area of the Clinton formation northeast of Marklesburg and in ferruginous sandstone elsewhere in area __ 4 Distribution. The Tuscarora crops out only along the crests 6. Shale, bluish - ______3 the small area 2J- miles northwest of McConnellstown. West of ridges, such as Tussey, Lock, and Dunning Mountains. 5. Sandstone, argillaceous, hard, fine grained, of Dunning and Lock Mountains the Keefer is represented by Character. The Tuscarora is a white or gray, medium greenish __--_--_..____.___....______2 a persistent bed of highly ferruginous and sandy limestone 4. Shale______-______-______.___--_.__-__ 2 thick bedded quartz sandstone, composed of medium-sized 3. Sandstone, hard 3-inch flags.___.__ ..___.___._ 1 5 feet thick and 60 feet below the top of the Clinton. Where transparent grains of quartz. In some groups of layers the 2. Shale: may have some thin.sandstone layers._ 30 not exposed it reveals its presence by a noticeable brown band 1. Sandstone, greenish and bluish gray, siliceous, quartz grains are firmly cemented together by interstitial hard, fine grained to bottom (No. 3 of rail­ in the soil. quartz deposited around the original grains in erystallographic road section below).__-______..______5 Beds above the Keefer member. Immediately overlying the continuity, making the rock a quartzite. It is these parts of 776 siliceous limestone bed representing the Keefer member in the the formation that constitute the best grade of ganister in the Section of the basal beds of the Clinton formation at a cut on the Pennsyl­ section at Lakemont, between Hollidaysburg and Altoona, region. Some layers, probably amounting to but a small part vania Railroad about half a mile west of Barree station and with varying details doubtless elsewhere west of Dunning of the whole, are composed of well-rounded, loosely cemented Clinton formation: Ft. in. and Lock Mountains, is 61 feet of shale containing thin lime­ 9. Shale, weathering purplish above. Equivalent grains, a few of which exceed 1 millimeter in diameter. Curi­ to lower part of No. 10 of tunnel section____ 50 stone bands and thin layers of lean ore extending up to the ously contrasted with the hard quartzite are occasional layers, 8. Shale, with sandstone layers 1 to 6 inches thick, McKenzie formation. East of Tussey Mountain the corre­ as much as 18 inches thick, of soft white, unctuous, and appar­ fine grained, greenish gray (No. 9 of tunnel sponding interval between the Keefer sandstone member and section)______..______.______.. 15 ently nonsiliceous clay. A number of such layers have been 7. Sandstone, ferruginous, red; "iron sandstone" the McKenzie seems to be about the same, but the rocks encountered in the quarry on the top of the south end of the of I. C. White______.._...______4 included are nearly all green, rusty-weathering, thinly fissile 6. Shale, green___...____.____...______.._____..____ 1 6 western offset continuation of Lock Mountain in the northeast 5. Sandstone, ferruginous, red, iron sandstone clay shale. Some small thin fragments only, suggesting rotten corner of the Hollidaysburg quadrangle. (Nos. 5-7 are equivalent to Nos. 8 and 7 of argillaceous limestone, were noted and White reports thin lime­ The bedding and attitude of the Tuscarora are shown in tunnel section)______4 stone in this part of the section half a mile east of Barree. 4. Shale, with fine-grained sandstone layers 2 to 4 Plate 15. inches thick (Nos. 6-2 of tunnel section)_____. 25 These beds are correlated with the Rochester shale. The hard, resistant character of this formation and its highly 3. Sandstone, hard, reddish and grayish green, Thickness. The thickness of the Clinton as measured at fine grained (No. 1 of tunnel section)______5 6 inclined attitude have caused the development of the sharp, steep 2. Shaly beds with thin firmer layers (not exposed Marklesburg, plus 61 feet for the thickness above the Keefer mountain ridges of the region, such as Tussey and Dunning in tunnel section)______8 sandstone member as measured at Lakemont in the Hollidays­ Mountains. These ridges are in general deeply covered near Tuscarora quartzite: burg quadrangle, is 776 feet. 1. Sandstone, thick bedded to massive, with Arth­ their crests with boulders ("scree") that have weathered off rophycus alleglianienxis______100± Age and correlation. Ulrich and Bassler 6 have published from the sandstone which crops out along the crests. These two sections give a very complete representation of an elaborate discussion of the stratigraphic relations and cor­ Thickness. The Tuscarora has a thickness of 400 to 600 the Clinton of this region, the western outcrops in Logan relation of the Clinton. They divide the formation into lower, feet in these quadrangles. Valley differing only in minor details such as the apparent middle, and upper Clinton; each division has three zones, and Age and correlation. Only one fossil, Arthrophycus alle- absence of the basal sandstone beds, the change of the Keefer each zone is marked by a characteristic assemblage of fossils. ghaniensis, supposed to be a cast of a worm burrow, occurs in sandstone member to a siliceous, ferruginous limestone, and the In these quadrangles the lower division of Ulrich and Bassler the Tuscarora quartzite. It is abundant, locally at least, near presence of the Frankstown ore at about the horizon of the extends somewhat above the Frankstown ore bed; the upper the top of the formation. This fossil characterizes the top of 2-inch layer of "keel" in No. 10 of the tunnel section. division extends downward about 50 feet below the Keefer the Albion sandstone (Thorold member) in New York and the Levant or "block" ore beds and red sandstone. Near the sandstone member; and the middle division lies between the Clinch sandstone of Virginia, so that the Tuscarora is cor­ base of the formation is a persistent red sandstone with which other two. The formation is fossiliferous, some parts of it related with the Albion on the north and with the Clinch on is locally associated the Levant or "block" ore bed or pocket abundantly. The species that are most abundant and that are the south. The Albion sandstone is the upper part of the as at Marklesburg. At an outcrop about 1,000 feet north of generally distributed throughout the formation are ostracodes, Medina sandstone as described in the older literature. The the old Frankstown mine 2£ miles northeast of Hollidaysburg bivalved crustaceans about a millimeter long, like the common lower part of the old Medina is now known as the Queenston it is a reddish thick-bedded, solid sandstone 10 feet thick. water fleas> of which Cypris is an example. Of these more shale, which is correlated with the Juniata formation of Penn­ Much red sandstone debris from this bed is scattered on the than 54 species occur in these quadrangles. In the bottom of sylvania, and this correlation supports the above correlation of lower slope of the south end of Brush Mountain. These red the Clinton, at the horizon of the " block ore," occur, in addi­ the Tuscarora. layers are reported to persist along the east side of Tussey tion to several species of characteristic ostracodes, the common STIAG-ABA GROUP Mountain to Maryland. They are similar in lithologic char­ Clinton fossils Coelospira hemispherica, Rafinesquina cf. R. Only one formation of Niagaran age the Clinton is rep­ acter to the red sandstone in the "Cacapon" formation of corrugata, and a Pterineaf closely allied to a Medina species. resented in this area. Virginia and are undoubtedly the thinned northern expression In the Frankstown ore and 6 to 10 feet above it ,are, besides 14 species of ostracodes, Coelospira hemispherica, Parmorthis CLINTON FORMATION of that type of sandstone. At Marklesburg the associated block ore was a fine oolitic ore 1 to 6 feet thick and clearly a pocket. aff. P. elegantula, and Calymene aff. C. blumenbachi. No col­ Name and definition. The Clinton was named for its So far as it was of workable thickness it has been mined out. lections were obtained from the middle division of the Clinton exposures in the town of Clinton, Oneida County, N. Y. Its Sandstone bed. Just above the Levant ore and red sand­ in these quadrangles, which here seems to lack the more stratigraphic limits in these quadrangles are the Tuscarora stone lies 15 to 40 feet of hard, fine-grained greenish or familiar Clinton forms. The upper division of the Clinton is, quartzite below and the McKenzie formation above. grayish sandstone (Nos. 9 and 10 of the preceding sections). on the contrary, profusely fossiliferous, and from it 59 species .Distribution. The Clinton crops out in a narrow belt along This bed crops out over a small area on the crest of the were collected, of which 36 are ostracodes. The other 23 the east side of the Tussey Mountain and the west side of Penn-Walker anticline about 2 miles northwest of Grafton. species are more especially characteristic of the Rochester shale Dunning and Lock Mountains and around the south end of It seems to be the Castanea sandstone of Swartz. of the Niagara Gorge, some of them for example, Dalmanites Brush Mountain. Hollidaysburg is situated upon the Brush Frankstown and other ore beds. In the vicinity of Holli­ limulurus being restricted thereto, as it is also to the part of Mountain area, of the formation. The best natural exposures the Clinton of this region above the Keefer sandstone. That daysburg, probably about 250 feet above the bottom of the of the formation are in the vicinity of Hollidaysburg, at Lake- Clinton, is the Frankstown ore bed, 8 to 22 inches thick, in part is therefore correlated with the Rochester shale, which is mont, at McKee Gap, and in the gorge of Frankstown Branch the midst of shale. The ore bed could not be examined, shown by paleontologic evidence to be represented by the upper of the Juniata west of Point View. because it does not show in outcrop, and mining ceased many 50 to 60 feet of the typical Clinton of eastern New York. Character. The Clinton is composed of shale and a small years ago. Fragments of ore picked up on the old dumps This shale of Rochester age constitutes the Drepanetlina clarki proportion of sandstone and limestone. Most of the limestone consist largely of small lenses, which were in part and probably zone of Ulrich. 7 The part of the upper division of the Clinton is in thin layers in the upper part of the formation, and some almost wholly formed by the replacement by ferric oxide of below the Keefer sandstone member is also proved by the of the sandstone is in thin layers in the middle part of the the shells of a small brachiopocl, Coetospira hemispherica, or evidence of fossils to be represented in the upper division of formation, but there are sandstone beds of considerable thick­ are internal moulds of the shells. the Clinton of New York and in the Alger formation of ness near both the top and the bottom. There are several thin Thin, lean ore beds that lie 200 to 300 feet above the Foerste in eastern Kentucky and southern Ohio, there being beds of hematite but not all are present at any one locality. Frankstown bed have been known in the region as the upper at least nine species of ostracodes common to the beds named. A section of all but the upper 50 to 100 feet was obtained The middle and lower parts of the Clinton in this region and double ore beds. They are exposed in some of the streets near Marklesburg, in the Huntingdon quadrangle, in a mine correspond to the part of the typical Clinton of eastern New of Hollidaysburg. tunnel that extends horizontally 1,000 feet through the steeply York below the main oolitic ore bed and to the lower two- In a section exposed at Lakemont the top 100 feet of the dipping Clinton beds to a point within about 10 feet of the top thirds of that part of the Red Mountain formation of Alabama formation contains a number of thin limestone bands and thin of the Tuscarora quartzite. This section is supplemented by a above the bottom of the "Big seam" of ore. The upper division ore bands that were not seen east of Tussey Mountain. Just section of the basal beds of the Clinton exposed in a railroad of the Pennsylvania Clinton is represented in Alabama by the above the Keefer sandstone representative in this section lies cut about half a mile west of Barree station, in the Tyrone upper 50 feet, more or less, of the Red Mountain formation, 12 to 18 inches of ore that represents the Roberts ore bed of which carries Dalmanites limulurus and other Rochester shale quadrangle. Both sections are given below. Maryland west of Tussey Mountain. fossils. Section on the east slope of Tussey Mountain 1 mile north of Marklesburg The Marklesburg bed, a typical Clinton fossiliferous hema­ CAYUGA GROTJP Feet tite 1 to 2 feet thick, lies just under the Keefer sandstone McKenzie formation : member, No. 12 of the Marklesburg section. It is known only To the Cayuga group of this area are assigned, in ascending Limestone and shale. order, the McKenzie formation, Bloomsburg redbeds, Wills Clinton formation : east of Tussey Mountain. 13. Shale, soft clay, weathers yellow (Rochester Keefer sandstone member^ The Keefer sandstone member Creek shale, and Tonoloway limestone. age).. ______-_- ... ___ ----- was named for its exposures on Keefer Mountain, in tile south­ MCKENZIE FORMATION 12. Sandstone, coarse, thick bedded, calcareous, ferruginous, fossiliferous; "Ore sandstone" west corner of Franklin County, Pa., especially at Warren Name and definition. The McKenzie formation was named of I. C. White (Keefer sandstone member)- Point, the south end of the mountain. It is the "ore sand­ for its exposures near McKenzie station, on the Baltimore & 11. Ore, fossiliferous; "fossil ore" of White. ______2±: stone" of White, 5 so called because it overlies the Markles- Section in tunnel: 6 Ulrich, E. O., and Bassler, R. S., American Silurian formations: Mary­ 10. Shale, soft; sandstone layers, greenish, thin, 5 White, 1. C., The geology of Huntingdon County: Pennsylvania land Greol. Survey, Silurian, pp. 255-260, 1923. fine-grained, yellowish, through 50 to 100 Second Geol. Survey Kept. T3, p. 133,1885. 7 Idem, pp. 349-353, 1923. Ohio Railroad west of Cumberland, Md. It includes the lime­ unknown in earlier formations, points also to an age later than codes have been found, most of which are new species or stone and the shale containing limestone layers that lie between Niagaran. The McKenzie is therefore correlated with the varieties. As the fossils specifically identified are now known the top of the Clinton as herein defined and the bottom of the basal part of the Salina formation of western New York. to be of rather uncertain stratigraphic value they afford no persistent overlying Bloomsburg redbeds. In the Hollidays- satisfactory ground.for correlation beyond indicating the Cayu- BLOOMSBURG B.EDBBDS burg region, as displayed in the fine section exposed at Lake- gan age of the Wills Creek. The presence of salt crystals mont, the formation begins at the base with a bed of "bouldery " The Bloomsburg redbeds formation was named for its expos­ in the Wills Creek shale and its position above the Blooms­ limestone and extends upward to the base of a bed of red shale ures at Bloomsburg, Columbia County, Pa. It includes the red burg redbeds suggest a correlation with the salt-bearing Camillus (Bloomsburg) which is well displayed around the foot of Brush shale and red sandstone immediately overlying the McKenzie shale member of the Salina. formation of New York. Mountain. East of Tussey Mountain the formation begins formation. The red shale and sandstone are prominently dis­ TONOLOWAY LIMESTONE below with the lowest well-developed limestone beds above the played along Redstone Ridge and other narrow wooded ridges Keefer sandstone member of the Clinton (about 60 feet above it) east of Tussey Mountain. There are especially good exposures Name and definition. The Tonoloway limestone was named and extends to the bottom of the red shale and red sandstone 1 mile northeast of Russeliville, 1 to 1-J- miles north and north­ for its exposures in the lower slopes of Tonoloway Ridge, in that crop out on Redstone Ridge. The McKenzie appears to cor­ east of Marklesburg, and on the river road in the gorge at the Washington County, Md. It includes more than the lower respond to the "upper Clinton shale" and "Barree limestones" south end of Canoe Mountain, in the northeast corner of the half of the Lewistown limestone of previous reports. It under­ of White, 8 except that White's upper Clinton includes the 60 Hollidaysburg quadrangle. It shows well in the road at the lies the Keyser limestone member of the Helderberg limestone feet or so of Clinton above the Keefer sandstone member. east base of the reservoir hill just east of Hollidaysburg, in the and overlies the Wills Creek shale. Distribution. The formation has the same general surface road about 1 mile southwest of Gaysport, and on the low ridge Distribution. The outcrop of the Tonoloway limestone, to­ distribution as the Clinton at the base of Brush Mountain, the east of Altoona and 1 mile south of the north boundary of the gether with the overlying Helderberg, makes a ridge parallel­ west base of Dunning and Lock Mountains, and the east base quadrangle. ing the base of Brush Mountain northeast of Hollidaysburg. of Tussey Mountain. The best exposures are at Lakemont East of Tussey Mountain the Bloomsburg is composed of The Tonoloway also crops out along the west slope of Lock and south of Gaysport. At other places, where not concealed fine-grained red sandstone, nonfissile lumpy red shale or mud- and Dunning Mountains, near the base. East of Tussey by wash from the mountain sides, the presence of the forma­ rock, and green shale, and west of Dunning and Lock Moun­ Mountain it crops out along the west side of Warriors Ridge tion is revealed by a limy soil and by fragments of shale and tains it is composed of red shale and impure limestone without to the north line of the Huntingdon quadrangle. The best fossiliferous limestone. sandstone. A section exposed 1 mile northeast of Russeliville exposures of the Tonoloway are in the railroad cut just east of Character. The McKenzie formation is composed of green­ has 15 layers 1 to 20 feet thick of the different kinds of rock, Hollidaysburg and in McKee Gap. The basal beds are ish clay shale with many interbedded thin layers of limestone among which there are two layers of red sandstone making exposed at points in the road along the east base of Brush and has near the middle one or more persistent layers of red 22 feet and six layers of red shale making 46 feet. The whole Mountain, and partial exposures along Warriors Ridge east of shale. Locally limestone predominates below and may even thickness exposed is 107 feet. A section exposed at the offset Tussey Mountain afford a fairly satisfactory knowledge of the almost wholly make up the lower 50 feet, as in the section at end of Lock Mountain is composed of limestone and red and limestone. Lakemont. The limestone is mainly dark gray, fine grained, gray shale, 10 beds in all, 2 to 25 feet thick, of which five are Character. The Tonoloway is prevailingly a thin-bedded or nongranular, and many layers are crowded with fossils. At red shale aggregating 41 feet; the full thickness exposed is to laminated dark fine-grained or nongranular limestone. the south end of the offset part of Lock Mountain, the 87 feet. A notable difference between the formation east of Layers 1 to 2 feet thick occur but compose only a small part McKenzie is composed of gray and yellowish-green shale with Tussey Mountain and that at the south end of Lock Mountain of the whole. Its general character is exhibited in the lower thin limestone layers crowded with fossils. Apparently above is. the absence of sandstone in the last and the small amount of part of the section 011 Bald Hill, east of Hollidaysburg, given the middle are two layers of red shale, the lower 15 and the limestone in the first. Farther west, in the vicinity of Lake­ below. upper 6 feet thick, separated by 6 feet of gray shale. Just mont and Hollidaysburg, the Bloomsburg redbeds is reduced Section of limestones at Bald ffitt, 1 mile east of Hollidaysburg above the upper shale is a layer of lean fossil ore 1 to 2 inches to one or two beds of red shale, apparently separated by gray Devonian Oriskany group: Feet thick. shale with limestone layers, and probably does not exceed 50 Ridgeley sandstone On the east side of Tussey Mountain the section is very feet in thickness. 24. Sandstone, exposed ______30± much like that at the south end of Lock Mountain. The for­ A very notable feature of the sandstone and limestone in 28. Limestone, thick bedded, siliceous ______20 mation is composed of shale with thin layers of argillaceous the Bloomsburg is the vertical cleavage, by which the beds are 50 divided into many small prisms. This cleavage is especially Shriver limestone: granular limestone and has near the middle a persistent band 22. Limestone, very evenly thin bedded, highly of red shale that is probably at the same stratigraphic horizon as prominent in the sandstone layers along Redstone Ridge, where siliceous, generally light gray, some dark the red shale at the south end of Lock Mountain. The follow­ it is so perfect in places that it has a very misleading resem­ layers; weathers to fine-grained yellowish sandstone (pi. 22) ______180 ing section, given by White, shows the thickness and com­ blance to vertical bedding. 21. Limestone, shaly, dark and dark bluish___ 75 position of the McKenzie. The hard sandstone beds of the Bloomsburg redbeds east of 20. Limestone, shaly, black, fissile, fossiliferous; Tussey Mountain make ridges and knobs, along which the contains Anoplotheca ______10 /Section of Staler tunnel No. $, 2 miles southwest of Coves rock crops out in many places in ledges marked only by trees 215 Bloomsburg redbeds: Feet and underbrush. Redstone Ridge is an example. Hiatus (Becraft limestone member of the Helderberg Concealed by surface debris _ 43 The thickness of the Bloomsburg is 50 to 150 feet. absent). Red rock_____..___- -.,.-_--_. _. 25 Helderberg limestone: Age and correlation. On lithologic grounds and strati- McKenzie formation: New Scotland limestone member: Shale, bluish green _._...._. ______...... 77 graphic sequence the Bloomsburg redbeds is correlated with the 19. Limestone, thick bedded, gray; contains Shale, red _..__.__....._. ....______-___. 70 Vernon shale member of the Salina formation. Eospirifer macropleurus ______10 Shale, olive ______. _. _... _ _ _ _ .. _ _....___..... 60 Goeymans limestone member: 18. Limestone, thick bedded, gray; contains Clay, blackish, originally limy ______.. 47 WILLS CHEEK SHALE Shale, olive and yellowisli-_____-.__..__. 48 Gfypidula coeymanensis ______12 Clay, blackish (decomposed limy beds) 82 Name and definition. The Wills Creek shale was so named Keyser limestone member: 17. Limestone, laminated; contains Leperditia 384 because it crops out along or near Wills Creek at Cumberland, gigantea and L. elongata______38 Clinton formation: Md. In reports of the Second Geological Survey of Pennsyl­ 16. Limestone, rather thick bedded, but beds Shale, olive and bluish gray _. 63 vania it was called Salina shale. It overlies the Bloomsburg really laminated ______46 Ore; fossils. 15. Limestone, rather massive, coarse grained__ 12 redbeds and underlies the Tonoloway limestone. 14. Limestone, appears like No. 15 but is really Thickness. The thickness of the McKenzie is about 200 Distribution. The Wills Creek shale crops out around the nodular; weathers to nodules and small feet in the Lakemont section and about 400 feet at the south pieces ; contains Favositeshelderbergiae and base of Brush Mountain, well up on the west side of Lock other fossils______12 end of the offset Lock Mountain and east of Tussey Mountain. and Dunning Mountains, and along the east side of Tussey 13. Limestone, massive, nongranular; contains Age and correlation.- The McKenzie is fossiliferous. Ostra- Mountain. Except on Lock and Dunning Mountains its out­ calcite veins and eyes______7 12. Limestone, thick bedded, but tends to weather codes are very abundant and many species are represented, but crop is in a valley or on low ground, as it is easily eroded. in laminae ; tubular stromatoporids in bot­ of other fossils only 10 species have been identified. Myriads The best exposures are along the highway southwest of Gays- tom. Nos. 12 and 13 are the "calico rock," of ostracodes lived in the water of the McKenzie sea, and the the quarry rock of the Hollidaysburg dis­ port and on roads leading to farmhouses east of the highway. trict______-______10 thin valves of their shells make up almost the whole of some Fairly good exposures may be seen at the east base of Brush 147 layers of rock, a. cubic inch of which contains not fewer than Mountain, 3 miles west of Canoe Creek. The belt of outcrop Silurian 50,000 valves, representing 25,000 individuals. The species east of Tussey Mountain shows many small exposures and Tonoloway limestone : are described and figured by Ulrich and Bassler. 10 much surficial debris. 11. Limestone, gray, thick bedded at top, lami­ nated below ; Leperditia alta abundant at The fossils afford no decisive evidence regarding the correla­ Character. The Wills Creek formation is composed almost top ______70 tion of the McKenzie. The ostracodes are nearly all peculiar wholly of thin, fissile gray shale that is probably calcareous 10. Limestone, thin bedded; has shale partings__ 5 to the formation. The other fossils are also either peculiar 9. Shale ______._-____-.._____.____ 2 where unweathered. The part of the formation overlying the 8. Limestone, thick bedded______.______8 for example, Reticularia bicostata or range through both Bloomsburg redbeds contains thin limestone layers near the 7. Shale______1 older and younger formations. In Maryland there is a larger base and some at other horizons. In the basal shale small 6. Limestone, thick bedded, blue ______.. 5 5. Shale, with red streak______..__ 1 nonostracode fauna, a considerable percentage of which occurs cavities filled with gypsum crystals occur here and there. The 4. Limestone, thin bedded _-______5 elsewhere in rocks of Rochester or Lockport age. These forms formation merges at the top into shaly limestone that is 3. Limestone___.._.______.___ 3 would support correlation of the McKenzie with the Rochester 2. Limestone, shaly_____.___._..____.______20 included in the next overlying formation. Not exposed______.__ 220 or Lockport. However, the Lockport dolomite, the youngest Thickness. The thickness of the formation, computed from 1. Limestone, shaly, probably near bottom of of the Niagara!) formations, thins out toward the east in the approximate average dip and the width of outcrop, appears Tonoloway ______90 central New York, and no beds of similar character occur to be about 400 feet. 430 in Pennsylvania, where the McKenzie lies between beds of Age and correlation. Leperditia cf. L. altoides and a small Total thickness of the section______824 Rochester age and the Bloomsburg redbeds. The Bloomsburg rhynchonellid are the only fossils found in the Wills Creek of As shown in this section, the Tonoloway is thick bedded at is overlain by the Wills Creek shale, which is abundantly Pennsylvania, but as reported bySwartz, 11 in Maryland the top, but the thick layers are laminated, and the formation as a proved by its fossils to be of Salina (early Cayugan) age. The formation has yielded a few more fossils, including such well- whole is distinctly thin bedded. The limestone is dark to Salina beds are composed in part of red shale, which is absent known species as Camarotoecliia litchfieldensis, Jfardenia inter- nearly black and fine grained; it appears to be rather impure in the Niagaran formations, so that the red shale of the striatus, "Spirifer"vanuxemi, Calymene camerata, and Leperditia and is perhaps somewhat rnagnesian. Thin layers of black McKenzie is believed to indicate that it is of Cayuga (Salina) alia. There is a new species of eurypterid, Dolichopterus chert occur in the top 10 feet of the section. A mile south of rather than Niagara age. The large assemblage of ostracodes, cumberlandicus, and a few fragments have been referred to Hollidaysburg layers of coarsely crystalline pinkish limestone Hughmilleria cf. If. shawangunk. About 17 species of ostra­ 8 White, I. O., op. cit., p. 382. and of a brown limestone with pebbles of the underlying shale 8 White, 1. C., op. cit., p. 161. 10 Ulrich, E. O., and Basher, R. S., op. cit., pp. 500-704, pis. 36-65, 1923. J1 Swartz, C. K., Maryland Geol. Survey, Silurian, p. 43, 1923. occur in the base of the Tonoloway. East of Tussey Moun- Holliday sbur jj-11un tin gdon 8 tain the Tonoloway has about the same character as at Holli- In these quadrangles the boundary between the Helderberg 8. Limestone, many cylindrical fossils (quarrymen's "hobnail rock," generally included in "calico daysburg. North of McConnellstown crystals of galena have and the underlying Tonoloway limestone is with some doubt rock") ______. ______1 been found in calcite veins along the west side of Warriors placed at the bottom of a bed of limestone known to the Tonoloway limestone : 2. Limestone, thick bedded, layers laminated (quarry- Ridge, and considerable money has been expended in pros­ quarrymen of the region as the " calico rock," or in some men's "ledge rock") ______5 pecting for lead ore without success. sections a few feet lower. The Helderberg is bounded above 1. Limestone, light gray, shaly; not utilized ______1 Thickness. The thickness of the Tonoloway exposed in the by the basal black shale of the Shriver limestone (No. 20 of Bald Hill section east of Hollidaysburg is 430 feet, and the the section at Bald Hill). 6. Section half a mile southwest of Graflon formation probably is thicker, as no beds are exposed in The Helderberg in this region and in Maryland is divided Helderberg limestone (Keyser limestone member): 10. Limestone, flaggy, Stromatopora abundant at top. the Bald Hill section like those at the bottom where it is into the Keyser limestone member at the base, the Coeymans 9. Not exposed ______exposed 1 mile south of Hollidaysburg. East of Tussey limestone member in the middle, and the New Scotland lime­ 8. Limestone, argillaceous, granular; contains Dip- Mountain the thickness appears to be 600 feet. stone member at the top. lontenopora siluriana, Fenestrellina altidorsata, Monotrypa corrugata, Orthopora regularise, Age and correlation. There seems to be no doubt of the Distribution. The Helderberg crops out near the crest of Camarotoechia litchfleldensis, Dalmanella identity of the Tonoloway of this region with that of Mary­ the ridge parallel to Brush Mountain from Altoona by way clarki, and Camarotoechia decker ensis- ______7. Limestone, with lenses of argillaceous limestone land. In Maryland 28 species of fossils have been obtained of Newry and Frankstown to the northeast corner of the and gray shale, much like bed No. 5; Atrypa from it, but in this region only a few species of Leperditia Hollidaysburg quadrangle, thence southward the outcrop fol­ "reticularis," Stromatopora, and cup corals are were obtained, mainly in the upper 50 feet, where they are lows the west flank of Lock and Dunning Mountains to the present ______8 6. Limestone, thick bedded, granular; contains Bato- plentiful in some layers. south edge of the quadrangle. The Tower Rocks, just south­ istomella interperosa, Fenestrellina cumberland- Ulrich says, in comparing the Maryland and New York east of Hollidaysburg, are in the Helderberg as are also the iae ?, Thamniscus regularis, arid Camarotoecfiia gigantea-.... _ _ ___. ______faunas: limestone quarries from Altoona to Canoe Creek. East of 5. Shale with limestone nodules.. . ______Comparison of these fossils with those of the New York section Tussey Mountain the Helderberg crops out along the west slope 4. Limestone, coarse, granular, thick bedded; cri­ leaves little doubt concerning the late Cayuga age of the formation. of Warriors Ridge, where a number of quarries mark its basal noidal layer of other sections but no crinoidal Most of the diagnostic species above listed occur in the Schoharie remains here; brachiopods near bottom ____ 6 part. Its full thickness is exposed at the Bald Hill cut, 1 mile 3. Limestone, flaggy and cherty, dark to black, chert Valley sections in N"ew York between the base of the Cobleskill and east of Hollidaysburg, and in a quarry near Allegheny Fur­ in thin layers and large thin lenses..______7 the top of the "Tentaculite" or typical Manlius limestone. A con­ nace, half a mile south of Altoona. 2. Limestone, dove-colored and dark bluish, amor­ siderable part of these species, it is true, passes upward in the phous, thick bedded ("calico rock ")_..______12 Maryland sections into the Helderberg limestone. * * * The Character. The Helderberg limestone is variable in char­ 1. Limestone; top seen __.______Manlius and Cobleskill therefore seem to be in general correlatable acter. Its general features are exhibited in the following 9. Section in old quarry half a mile northwest of Cove with the Tonoloway, although the fauna indicates that Tonoloway sections and in the section at Bald Hill given on page 7. sedimentation in Maryland in part preceded that of the Manlius and These sections with others are shown in graphic form in Helderberg limestone: Ft. in. Cobleskill in New York. 14. Limestone, irregularly bedded, partly exposed Figure 3. (mostly Keyser member but probably in­ There are, however, some features of the faunas of the Coble- 1. Section of quarry at Allegheny Furnace, half a mile south of Altoona cludes Coeymans and New Scotland at top) _ 150_fc 13. Limestone, impure, nodular bed (No. 14 of Bald skill and Manlius that throw doubt on the validity of this Helderberg limestone: Feet New Scotland and Coeymans (?) limestone members: Hill section) ______..______correlation. 12. Limestone, thick bedded, crowded with cri- 9. Limestone, thick bedded, cherty______10 noid joints ______Keyser limestone member: DEVONIAN SYSTEM 11. Limestone, cherty, largely made up of chert 8. Limestone, mostly thin bedded, dark shaly layers 1 inch thick with wavy surface as if layerat bottom.______-___.__--____ 30 The Devonian system in these quadrangles includes the composed of coalesced nodules ____.____ 7. Limestone, thick bedded, gray ______10 following formations, beginning with the lowest and oldest: 6. Limestone, very dark, nodular; nodules prob­ 10. Limestone, shaly; Bryozoa and other fossils Helderberg limestone, 150 to 200 feet; Oriskany group, com­ ably Stromatopora heads___. ______3 present____. ______From beds 10 to 14 inclusive, but only from 5. Limestone, thin bedded ______12 posed of the Shriver limestone below, 200 to 300 feet, and the the very bottom of bed It, the following fos­ 4. Limestone, thick bedded, crystalline___ __. 55 sils were collected: Cyathophyllum clarki, Ridgeley sandstone above, 50 to 100 feet; Onondaga forma­ 3. Limestone, nodular bed ______8 C. radiculum, Favosites pyi'ijormis, Atrypa 2. Limestone, thick bedded ("calico rock") _____ 12 tion, 50 feet; Marcellus shale, 200 to 300 feet; Hamilton bfconvexa, A. "reticularits,'1' Camarotoechia formation, 800 to 1,200 feet; Portage group, comprising the 140 cf. C. altiplicata, Leptaena "rhomboidalis," 1 ONE-HALF MILE SOUTH OF ALTOONA QUARRY BALD HILL CUT Near Allegheny Furnace One mile east of Hollidaysburg

9 OLD QUARRY One-half mile northwest BROWNS QUARRY of Cove McConnellstown

Nodular Crinoidat

Cherty

Densely Thick bedded, crinoidal dove colored; main quarry rock; Dark, compact calcite veins with calcite ("calico rock")

Dark, fine grained; Stromatopora abundant; Leperditia

FIGURE 3. Detailed columnar sections of the Helderberg limestone in the vicinity of Hollidaysburg and along Warriors Ridge. Harrell shale belotv and the Brallier shale above, 1,600 to Tonoloway (?) limestone: Merista typa, Neucleospira elegans, Rhlpido- 1. Limestone, thick bedded. 15 mella cf. R. preoblata, Rhynchospira globosa, 2,050 feet; Chemung formation, 2,400 to 3,400 feet; and Gypidnla coeymanensis var. prognostica, Hampshire formation, 2,000 to 2,500. In the Hollidaysburg 3. Section of lower part of Helderberg limestone in Smith's quarry, on and Delthyris octacostata. ridge half a mile west of Frankstown 9. Limestone, thick bedded, a mass of crinoid quadrangle the total thickness of the Devonian, is 7,465 feet, stem plates; Gypidula coeymanensis var. Helderberg limestone (Keyser limestone member): Feet prognostica, or Merista typa, present in very and in the southeast corner of the Huntingdon quadrangle, 7. Limestone, medium thick bedded, crystalline_____ 10 where the rocks are nearly vertical, the total thickness deter­ bottom __.__.______10 6. Limestone, argillaceous, nodular; contains cobbJy 8. Limestone, dark, nongranular; part thick and mined from the width of outcrop is more than 8,000 feet. layer (quarrymen's "bogus rock") ______._' 3 part thin bedded; weathers rough and 5. Limestone, massive, gray, flecked with white and cavernous; veined with calcite; one layer IIELDERBERG LIMESTONE yellow calcite eyes and veins; upper 10 feet full of crowded with a species of Striatopora?-----. 10 Stromatopora heads ("calico rock") ___-______-_- 25 Name and definition. The Helderberg limestone was named 4. Limestone, thick bedded, light gray (silver-gray for its exposures in the Helderberg Mountains, in New York. rock, generally included in "calico rock"?)__ _ 2-4 9

Tonoloway (?) limestone: Ft. percentage of the Keyser fauna, including many species that Character. The Ridgeley is in part a.pure quartz sand­ 7. Limestone, very dark, fine grained, medium thick bedded; crowded with Stromatopora occur in Maryland and New Jersey, are new or belong to stone, in many places conglomeratic, some layers or lenses below; a few fragments of Leperditia and genera that reach their maximum development in the Devo­ being full of quartz pebbles an eighth to a quarter of an inch other fossils eeen, including a large high- spired gastropod. ____..____.______..___.._ nian, and on the principle that the age of a bed is that of its in diameter. In part the Ridgeley in the fresh condition is so 6. Limestone, fine grained, with wavy and sandy youngest species the Keyser has been referred to the Devonian limy that the rock has the appearance of limestone.. Near the laminae..- ______.__.._...._...______._ by Ulrich and Schuchert, and that assignment has been gen­ bottom in the railroad cut just east of Franks town lie thick 5. Limestone, dark, nongramilar...._--_.. ..._....__.___ 4. Limestone, dark, laminated...... __..____.____._..___ erally accepted. beds made up of interlocking wedges, in some of which cal­ 8. Limestone, thick bedded, dark, i.iongranular__ Fossils from the upper 25 feet of the Helderberg include careous material and in others sandy material predominates. 2. Limestone, laminated but compact....____. .__..__ Gypidula coeymanensis, Eospirifer macropleurus, Spirifer per- 1. Limestone, shaly, dark, sun cracked, Leper- On complete leaching the limy rock crumbles to loose sand, dilia present. (Top of several hundred feet lamellosa, and Stropheodonta beckii. Gypidula coeymanensis which is used for mortar and other purposes. On Robinson of such, beds.) is the guide fossil of the Coeymans limestone, and Eospirifer Run east of Hollidaysburg there is at the top a highly ferru­ Thick ness. The thickness of the Helderberg in the vicinity macropleurus and Delthyris perlamellosa are equally character­ ginous red rock 1 foot thick not seen elsewhere. of Hollidaysburg is about 150 feet and east of Tussey Moun­ istic of the New Scotland member. The general character of the Ridgeley is well displayed in a

tain about 200 feet. HIATUS BETWEEN HEI.DERBERG .LIMESTONE AND OBISKANY GROUP quarry at Allegheny Furnace, in which the whole or nearly Keyser limestone member. 12 - The Keyser member was named the whole thickness is exposed. No indication of the presence of the Becraft limestone has for exposures at Keyser, W. Va. At the bottom of the been found in these quadrangles, and it is surely absent in Section of Ridgeley sandstone at Allegheny Furnace Keyser is the quarry men's "calico rock," which is thick- places at least, so that there is a slight hiatus between the bedded to massive, mostly dove-colored but variegated with Feet Helderberg and the Oriskany. 1. Sandstone ______10 white, pink, or yellow calcite veins and eyes, to which its com­ 2. Sandstone, thick bedded, calcareous; contains near the mon designation is due. East of Tussey Mountain the " calico ORISKANY GROUP top lenses of quartz conglomerate 1 foot thick, also layers of shell conglomerate densely packed with shell rock" is succeeded by coarse crinoidal limestone and cherty Name and definition. Oriskany sandstone is a long- fragments ______82 limestone 12 to 19 feet thick (fig. 3, section 6-8) in which the established name, from Oriskany Falls, Oneida County, N. Y. 8. Sandstone______..____ 3 chert and limestone occur in alternating layers 1 inch or so In this region the Oriskany is overlain by the Onondaga 45 thick. In the vicinity of Hollidaysburg there are no beds of formation and underlain by the Helderberg limestone and has East of Tussey Mountain, along the crest and east slope of this character, and the "calico rock " is succeeded by a highly two distinct lithologic divisions corresponding to those in Warriors Ridge, the Ridgeley is a coarse, thick-bedded, loosely fossiliferous limestone 3 to 12 feet thick. When not weathered Maryland, the lower of which has been named the Shriver cemented quartz sandstone, some layers of which easily crumble this bed appears like solid limestone with wavy laminae chert and the upper the Ridgeley sandstone. Those names to sand in the hand. It has been quarried for sand at a few inclosing small lenticular bodies or nodules, and these nodular are adopted here, but the divisions are given the rank of for­ points. layers are characteristic of the Keyser member. On weather­ mations and the Oriskany is given the rank of a group. In Thickness. If part of the Ridgeley at Allegheny Furnace ing the bed disintegrates to a crumbly dirty-white or gray this area the Shriver is more appropriately designated the is not exposed the total thickness may be 55 to 60 feet, but mass surrounding the nodules, some of which at least are small Shriver limestone. generally in the Hollidaysburg quadrangle the thickness heads of the coral Favositvs helderbergiae. SHRIVER LIMESTONE seems not to exceed 50 feet. At Huntingdon and southwest- In the Bald Hill cut and in the quarry near Allegheny Name and definition. The Shriver limestone was named for ward, along Warriors Ridge, the thickness is probably a little Furnace the part of the Keyser above the nodular layer is Shriver Ridge, on the outcrop of the formation near Cumber­ more than 100 feet. fully exposed and is made up of coarsely crystalline, thick- land, Md. L C. White applied the name Stormville shale to Age and correlation. The Ridgeley is abundantly fossilifer­ bedded gray to dark limestone 12 to 20 feet thick at the the Shriver limestone because he correlated the Shriver with ous. The 38 forms collected constitute a characteristic upper bottom and 75 to 90 feet of thick-bedded but more or less his Stormville shale of eastern Pennsylvania. According to Oriskany fauna, which is conclusive evidence for correlating laminated limestone at the top. (See pi. 21.) In the top of Weller, however, White used the name Stormville for sand­ the Ridgeley sandstone with the typical Oriskany sandstone this part in the Bald Hill section is a thin layer containing stones of Helderberg age also, and he also applied the name to of New York. A few of the more diagnostic species are numbers of the notably large species of Leperditia, L. elongata a limestone in eastern Pennsylvania. Because of these differ­ Mdriocrinus sacculus, Coslellirostra peculiaris, Herislella lata, and L. giganteo. The Keyser is 100 feet thick in the Holli­ ent uses the name Stormville has been superseded in the Rensselaeria elongata, Costispirifer arenosus, Diaphorostoma daysburg region and somewhat thicker east of Tussey Mountain. Hollidaysburg-Huntingdon region by the exactly defined ventricosum, and Platyceras gebhardi. Coeymans and New Scotland limestone members. The divi­ name Shriver. sions of the Helderberg limestone long known by the paleon- ONONDAGA FORMATION Distribution. The Shriver limestone is persistent through­ tologic terms "Lower Pentamerus" limestone and " Delthyris out the quadrangles, its surface distribution being in a narrow Name and definition. The Onondaga formation was named shaly" limestone have been renamed the Coeymans limestone belt parallel to that of the Helderberg limestone. The only for its exposures in Onondaga County, N. Y. In New York arid the New Scotland limestone respectively. Both names are complete exposure of the formation is in the east side of the the name Onondaga as now applied includes the long well- derived from villages in Albany County, N. Y. Bald Hill cut, 1 mile east of Hollidaysburg. The bottom 80 known " Corniferous limestone." In this region the Onondaga In the Bald Hill cut (section 2) and in the quarry near feet is exposed in a quarry in the south environs of Altoona. includes dark shale with limestone beds, in all 50 feet thick, Allegheny Furnace (section 1) these members consist of rather Character. The Shriver limestone is composed almost extending from the Ridgeley sandstone below to the highly thick-bedded gray medium-grained limestone with dense gray wholly of thin-bedded to laminated highly siliceous limestone. fissile Marcellus black shale above. chert in thin layers. Chunks of this chert scattered on the (See pi. 16.) At the bottom of the section 1 mile east of The Onondaga beds were recognized by White 1 8 as a surface elsewhere indicate the presence of the parent layers Hollidaysburg (p. 7) is a bed of black shaly limestone, and distinct lithologic subdivision but were classed as lower Mar­ beneath. Limestone one-third of a mile west of Grafton, with other layers may weather to a shaly condition. On weather­ cellus. They were also recognized by Platt, 14 who distinctly fine large specimens of .Eospirifer macropleurus, a typical New ing the thin layers of the main body of the Shriver are leached referred them to the Onondaga ("Corniferous") horizon. Scotland fossil, proves the presence of the New Scotland east of their calcareous matter and break down into small sandy Distribution. The Onondaga is persistent in the region. of Tussey Mountain. pieces about the size of the hand and half an inch thick, which It shows near the highway just east of the limestone cut at In the Bald Hill section 10 feet of noncherty limestone is fill the soil or thickly strew the surface (pis. 17, 18) and make Bald Hill, about 1 mile east of Hollidaysburg; in the road assigned to the New Scotland and 12 feet of cherty limestone the location of the outcrop of the Shriver easy. The sandy about 1 mile nearly west of Canoe Creek post office; near the to the Coeymans. Elsewhere the two were not separated. pieces are exceedingly fine grained, and some pieces have a road in the extreme southwest corner of the Hollidaysburg Their combined thickness is 20 to 25 feet. cherty aspect on fresh fracture. quadrangle; in the southeast corner of the Hollidaysburg Age and correlation. Except for the basal "calico rock," Thickness. The Shriver is 200 feet thick in the railroad cut quadrangle near the junction of the roads just west of Cove which has not been recognized elsewhere, the Keyser of this at Bald Hill and appears to be 200 to 300 feet thick east of station; in the western outskirts of Huntingdon near the region can easity be identified lithologically with the Keyser Tussey Mountain. reformatory and along the vallej' southwest of the reformatory, limestone member of the Helderberg at Keyser, W. Va., and Age and correlation. Fossils are scarce in the Shriver but where an abundance'of fine debris marks its position. at localities in Maryland. 32 species have been collected which serve to establish its lower Character. In these quadrangles the Onondaga formation A species of Striatopora is abundant in the "calico rock" Oriskany age. Among the more significant are Technocrinus is mostly shale. The following section represents well its half a mile northwest of Cove, and a cylindrical fossil, prob­ cf. T. andrewsi, Chonetes hudsonicus, Pholidops cf. P. tamida, general composition: ably a tubular Stromatopora, occurs in the bottom of the "calico and Thlipsura (CratereUma) robusta. The last species is known rock" in the Hollidaysburg region, where in some places indi­ Section in highway near head of Robinson Run, Hollidaysburg from the Shriver only. viduals are so common as to suggest the names "hobnail rock" quadrangle to the quarrymen. Fossils are fairly plentiful in the nodular RIDGELEY SANDSTONE Marcellus shale: yeet Shale, black. and other beds immediately above the "calico rock," but in the Name and definition. The Ridgeley sandstone was named Concealed___..______._.__ 20 still higher beds they are so firmly embedded in the matrix for Ridgeley, W. Va., opposite Cumberland, Md. Shale, black______.______l that they can not easily be removed in a condition to identify. Shale, greenish gray _..__.______.______.,.,5 Distribution. Though the Ridgeley is thin it is persistent, Onondaga formation: Within 30 feet above the "calico rock" 37 forms were and evidence of its presence is seen wherever its outcrop is not Limestone; contains fossils..______1 collected. concealed by debris from the ridges. Its outcrop can be easily Shale, greenish, weathering gray ______2 In Maryland and West Virginia the Keyser is subdivided Limestone______.______followed from Altoona, encircling Scotch Valley, to McKee Shale, greenish calcareous bands ______12 into the Chonetes jerseyensis zone below, which includes about Gap; thence the outcrop is concealed southward along the Limestone, dark; contains fossils ______1 three-fifths of the entire thickness, and the Favosites helder- Shale, gray with streaks of black______20 west base of Dunning Mountain to Boiling Spring Run, Shale, black, fissile, fossiliferous______5 bergiae var. praecedens zone above. Most of the fossils identi­ whence the sandstone can be followed to the south line of the Shale, greenish gray __.._____. ______1.0 fied in these quadrangles occur in the Chonetes jerseyensis zone quadrangle, beyond which it is finely displayed on the hills Shale, bluish, calcareous; weathers cirab, fossiliferous 5 Not exposed_.______-______.______10 of Maryland, from which it appears that the lower 40 feet of in Kimmell Township. The conglomeratic layers of the the Keyser of the Hollidaysburg-Huntingdon region is in the Ridgeley are especially well displayed in the quarry at Alle­ Chonetes jerseyensis zone. gheny Furnace (see section below) and on the ridge half a Ridgeleysan dstone: The Keyser limestone can be definitely correlated with the Red rock, highly ferruginous-_....______1 mile nearly due north of Flowing Spring. East of Tussey Sandstone__.______.___ 20± Decker limestone of New Jersey. Mountain the sandstone crops out along the east slope of Everywhere the Onondaga has limestone at the top and As many of the Keyser species existed in Silurian time, Warriors Ridge, which is approximately a dip slope on the shale in the lower part. The limestone is dark gray and some geologists hesitate to accept the Devonian age of the Ridgeley. Due west of Huntingdon this outcrop on the dip- argillaceous and looks earthy after*weathering. The shale is Keyser, preferring to regard it as Silurian. A considerable slope is more than a mile wide, owing to the low southeast dip of, 5°-10°. The sandstone is best displayed in a cut on the 18 White, 1. C., op. cit., p. It4. l " A number of geologists, as C. K. and F. M. Swartz, are now inclined to 14 Platt, Franklin, Geology of Blair County: Pennsylvania Second Geol. class the Keyser as Silurian instead of Devonian. railroad just west of Huntingdon. Survey Kept. T, p. 34, 1881. Hollidaysbiirg-Muntiiigdoii 10

dark green or bluish, and some bands are calcareous. Both /Section of Hamilton formation at tJie brick worJcs at South Altoona with Hypothyridina venustula, which is the chief guide fossil of shale and limestone are sparingly fossiliferous. Feet the Tully limestone. The Tully has generally been classified Thickness. The thickness of the Onondaga is 50 to 70 feet, Burket black shale member of the Harrell shale of the as the basal bed of the Upper Devonian, but evidence for its Portage group: Aye and correlation. The position of the beds here de­ 15. Shale, black, fissUe ...-__ _ . -. 10 high Middle Devonian age has been published. scribed, between the Oriskany below and the characteristic 14. Shale, brown______. 4 fissile black shale of the Marcellus above, which is the same as 13. Shale, black; contains fossils.______5 12. Shale, brown (paper shale); contains fossils___---_- 5 Name and definition. The name Portage has long been in the position of the Onondaga limestone in the type locality in 24 use for the shales and sandstones typically exposed in the New York State, points almost conclusively to the equivalence Hamilton formation: gorge of the Genesee River in western New York, between of the beds with the Onondaga. 11. Shale, green, calcareous, highly fossiliferous. ______2 Portageville and Mount Morris. In these quadrangles the Forty-five species of fossils have been collected from the 10. Limestone, highly fossiliferous_____--__-______1 9. SI)ale, mostly green, some very dark, very fossil­ Portage rocks are overlain by the Chemung formation and Onondaga in these quadrangles, but as most of them, exclusive iferous at bottom.______10 underlain by the Hamilton, two intervening formations, the of the trilobites, occur in the Oriskany or Hamilton also, their 8. Limestone, nodular, not persistent, very fossilifer- Genesee shale and Tully limestone, except for a foot or two of evidence as to the age of the formation is not satisfactory. ons ______7. Shale, green, hackly______..______limestone, mentioned above, apparently not being represented Nine species of trilobites from this region or from the same 6. Limestone, like No. 10______here. In this region the Portage group is divided into the formation elsewhere in this or adjoining States are, according 5. Shale, dark olive-green, hackly, with sandstone in layers 1 foot thick or less______.______180 Harrell shale below and the Brallier shale above. to Kindle, not known except in the Onondaga and assure the 4. Shale, dark olive-green; few thin sandstone layers. 200 Onondaga age of the formation here described. The trilobites 3. Concealed ______.._.....__ 280 HAKREM, SHALE are Acidaspis callicera, Conolichas hispidus, Otarion cf. 0. 2. Shale, olive-green, soft ______Name and definition. The Harrell shale was thus named Marcellus shale: stephanophora, Coronura aspectans, Lichas (Araes) contusus, 1. Shale, black, fissile. because it is well displayed at Harrell station, about 6 miles Odontocephalus aeyeria, 0. selenurus, Phacops cristata, and P. 773 northeast of Hollidaysburg. It is the lowest formation of the cristata var. pipa. The rocks become more sandy and less fissile within 100 to Portage group of this area and is underlain by the Hamilton MARGE LI/US SHALK 150 feet above the bottom, and partial sections at other points, formation and overlain by the Brallier shale. probably falling in the position of the concealed space (No. 3 Distribution. The Harrell shale crops out along the west Name and definition. The Marcellus shale was named for of the section above), show considerable fine-grained sandstone, side of Logan Valley and around the Scotch Valley basin. exposures at Marcellus, N. Y. It overlies the Onondaga for­ in evenly bedded layers generally not more than 1 foot thick The gray shale facies is best exhibited on the Pennsylvania mation and underlies the Hamilton. and cut by joints into smooth, even-faced, sharp-edged rhom- Railroad in the western outskirts of Altoona, in the shale pits Distribution. The Marcellus shale is well exposed at the bohedral blocks that are very distinctive. The upper olive- at the Eldorado brick works, and at Harrell. East of Tussey head of Robinson Run, in the railroad cuts and shale pits near green hackly shale, No. 5 (pi. 19), is also very distinctive, Mountain it crops out along the west side of Middle Ridge and South Altoona, in the bed of Fraukstown Branch of the and the presence of this part of the Hamilton may commonly of Piney Ridge north of Aitch. The best exposure is at the Juniata 2 miles north of Claysburg, at several points in the be detected by its debris scattered on the surface. Both the west base of Middle Ridge, in the road 1 mile southwest of valley southwest of Loop, and in the road crossing the valley limestone and the hackly shale, Nos. 6 to 11 of the above Aitch, where the section given below was obtained. A small three-quarters of a mile north of Loop. There are good section, are very fossiliferous, but fossils are scarce in the rest thickness of black shale is exposed in the road just above the exposures also near Huntingdon and along the Huntingdon & of the formation in Logan Valley. park immediately east of Standing Stone Creek at Huntingdon. Broad Top Mountain Railroad, especially for 2 or 3 miles The general character of the Hamilton east of Tussey Moun­ Character. The Harrell shale at Altoona and west of northeast of Cove. As the Marcellus and the immediately tain is illustrated by the following section : Dunning and Lock Mountains includes at the base a persistent overlying Hamilton shales are soft and easily erodible, valleys stratum of apparently unbroken black fissile shale (Burket have been formed along their outcrops. Such valleys are Section of Hamilton formation in northeast corner of Everett quadrangle, black shale member). This is overlain by very soft brownish- followed by Frankstown Branch from Frankstowri to the 2£ miles southwest of Cove station gray or olive-green, highly fissile shale that cleaves into paper- south edge of the Hollidaysburg quadrangle and by the Hamilton formation: Feet thin laminae of considerable size and uniform thickness. The Huntingdon & Broad Top Mountain Railroad south of 9. Shale, olive-green, stiff, nonfissile, hackly, lumpy black shale is the harder and cleaves into small thin chips; the or crumbly (mudrock), highly fossiliferous; top McConnellstown. not exposed ______gray shale is much softer, and although it shows lamination Character. The Marcellus is a widespread formation in 8. Shale, dark, fissile, with thin sandstone layers._. 160 cleavage in outcropping faces where it has been cleanly 7. Not exposed, shale ddbris, yellow-green, probably New York and Pennsylvania and preserves the same lithologic shale like No. 8______exposed in cuttings it readily decomposes to clay. These two characteristics throughout except that in its type section in New 6. Sandstone, gray to greenish, flaggy, fine grained divisions are sharply separated in the western area in Logan York its upper half or so is a gray shale. With this exception 5. Not exposed.______Valley, but east of Tussey Mountain the Harrell is composed 4. Shale, dark, fissile______100 it is a black fissile shale, the black color being due to carbon­ 3. Sandstone, fine grained, dark bluish when fresh; of alternating comparatively thin beds of black shale and soft aceous matter. In the vicinity of Huntingdon there are many weathers rusty, flaggy.______-....______75± brown shale, which are lithologically identical respectively 2. Shale, rusty-weathering above, gray-weathering large calcareous concretions in the Marcellus and a few limestone below, dark, soft, fissile __^______350 with the black and gray shales of Logan Valley just described layers that possibly should be included in the Onondaga. but differ in their distribution through the section. The char­ 1,170± Thickness. The thickness of the Marcellus is 150 to 200 Marcellus shale: acter of the Harrell in this region is shown in the following feet, being perhaps a little greater east of Tussey Mountain 1. Shale, very black, fissile. section: than west of Dunning and Lock Mountains. The two sandstone beds shown in this section are prominent Section of lower part of Harrell shale 1 mile southwest of Aitch Age. The lithologic character and the stratigraphic position members of the Hamilton in Raystown Valley and form con­ of this body of black shale, which apparently correspond Harrell shale: Feet spicuous ridges. The ridge between the Huntingdon & Broad Shale, fissile, dark but not black______60 closely with those of the typical New York Marcellus, leave no Top Mountain Railroad and Warriors Ridge, extending from Shale, black______20 doubt as to its identity with that formation, and this identity Shale, gray______.___ 25 Huntingdon to McConnellstown, was made by the lower sand­ Shale, soft, dark and black alternating in compara­ has been recognized by all geologists who have worked in the stone. These beds were called by White the lower and upper tively thin layers______..___..__ 40 region. Fossils are very scarce in the Marcellus of this region, Hamilton sandstones, and the three shale divisions were called 145 but some were collected. Of these forms Leiorhynchus limi- by him the lower, middle, and upper Hamilton shales. Hamilton formation; Shale, green, hackly. tare, which makes its appearance in the Marcellus, is but rarely Except for these sandstones the Hamilton in this part of the reported from higher beds and may be regarded as an index area is lithologically the same as in Logan Valley. The thin Owing to this distribution in comparatively thin alternat­ fossil for the Marcellus. limestone layers in the top may be seen in the road east of ing layers the Harrell cannot be subdivided east of Tussey Cove station. Under the limestone is the same lumpy, crum­ HAMILTON FORMATION Mountain, as it is west of Lock and Dunning Mountains, yet bly, fossiliferous olive-green shale or mudrock as that at the there is no doubt of the exact equivalence of the Harrell in Name and definition. The Hamilton formation was named top of the Hamilton in Logan Valley. both areas. for its exposures in the vicinity of Hamilton, Madison County, Thickness. In Logan Valley and west of Dunning Moun­ Thickness. The thickness of the Harrell in both the Holli­ N. Y. In these quadrangles it is underlain by the Marcellus tain the thickness of the Hamilton is about 800 feet; east of daysburg and Huntingdon quadrangles is 200 to 250 feet. shale and overlain by the Portage group, two intervening for­ Tussey Mountain it is about 1,200 feet. Burlcet blade shale member. The Burket black shale mem­ mations of the New York section the Tully limestone, except Aye and correlation. The Hamilton age of the rocks ber of the Harrell shale was named for Burket, 1 mile possibly a foot or two, and the Genesee shale apparently being described here is satisfactorily demonstrated by their strati- southwest of Altoona, where this shale is well displayed. absent in this region. graphic relations, their lithologic character, and their abundant Throughout the Hollidaysburg quadrangle this member is an Distribution. The Hamilton crops out in a belt of uneven fossils, and they have been accepted as Hamilton by all geolo­ unbroken :mass of very black and highly fissile shale 80 feet width from Altoona around the south point of the Brush gists who have seen them. The collections of fossils comprise thick. It crops out in a continuous band from Altoona south­ Mountain anticline, around Scotch Valley, and southward 9 corals, 3 crinoids, 14 bryozoans, 41 brachiopods, 39 pelecy- west to Queen just west of the southwest corner of the Holli­ along Frankstown Branch to the southwest corner of the pods, 13 gastropods, 2 cephalopods, 3 pteropods, and 7 ostra- daysburg quadrangle and around a large area in the center of Hollidaysburg quadrangle. The outcrop east of Tussey Moun­ codes. Of these 121 species, 113 occur in the upper 25 feet of Scotch Valley. It is well exposed in Altoona at and near the tain is confined to a long, narrow belt just east of Warriors the Hamilton and mainly in beds 6 to 11 of the section at intersection of Fourteenth Street and Thirteenth Avenue, Ridge and parallel to it. The dip is steep in the south end of South Altoona. under the schoolhouse at Burket, on the road 2 miles south­ this belt, and the outcrop is consequently narrow, but the dip Nearly all the species in these extensive collections occur in west of Claysburg, and at Harrell station, in Scotch Valley. decreases gradually northward to 10° at Huntingdon, so that the Hamilton of western New York, and most of them are There are excellent exposures along the Pennsylvania Railroad there the outcrop is 1 mile wide, and the city is built upon the known only from/the Hamilton. for 2 or 3 miles northeast of Altoona. formation. Certain species of fossils such as Chonetes aurora, Echinocoelia Age and correlation. The Harrell shale contains a few very Besides the localities at which the sections given below were ambocoelioidesf, and Emanvella subumbona demand special small species of fossils, which are rather generally distributed measured, the greater part of the Hamilton is exposed at the comment because they prove the horizon of the Tully limestone. through the formation. Some of the species are fairly abun­ south end of the knob just east of East Freedom, at several They occur in a limestone about 1 foot thick included in the dant for example, Paracardium doris and Pterochaenia fra- points around Scotch Valley, and in Huntingdon and vicinity. Hamilton as the top layer, immediately in contact with the over­ gilis. Styliolina fissurella is very abundant, as usual in the Character. The Hamilton is composed principally of shale. lying Burket black shale member of the Harrell shale, of the Devonian black shales of the northeastern United States. The West of Dunning and Lock Mountains very little sandstone is Portage group. All three were found 1 mile southwest of Burket black shale member also contains most of the species present, but east of Tussey Mountain there are two persistent Claysburg, in the Hollidaysburg quadrangle, and the first and that were collected from the other parts of the Harrell shale, sandstone beds which divide the shale mass into three nearly last with Leiorhynchus sinuatus 1 mile southeast of Cove station, and most of the species are present east of Tussey Mountain equal parts. Its general character west of Dunning and Lock in the southwest corner of the Huntingdon quadrangle. In at the very base of the Harrell, where the black facies is Mountains is shown in the following section: New York and parts of Pennsylvania Chonetes aurora occurs much less strongly developed. The most important fossils for correlation are Chonetes lepida, Buchiola retrostriata, Ontaria member of the post-Rhinestreet mass, are singularly like the Ft. in. 31. Not exposed ______..______200 acoinda, Paraeardium doris, Manticoeeras patersoni, and Pro- Brallier shale in lithologic character. The Brallier certainly 30. Shale and sandstone______15 beloeeras lutheri. In a railroad cut 3 miles northeast of Altoona includes the equivalent of the Gardeau and probably is to be 29. Not exposed______,._____._ 100 28. Sandstone______20 a fine specimen of a goniatite, apparently a new species of correlated with all of the Portage above the Rhinestreet. The 27. Shale______4 Sandberyeroceras, was obtained from this shale. Although a total thickness of the Portage formation in the Portage section, 26. Shale, with thin sandstone ______5 number of these fossils, as Styliolina and Pterochaenia, occur with which the Brallier is correlated, Hatch shale to Wiscoy 25. Sandstone ______'____'______13 24. Shale____^._:______29 in the Genesee shale and older beds, the assemblage as a shale, inclusive, is 978 feet. If the correlation is correct, the 23. Shale, with thin sandstone layers__..___ 4 6 whole is characteristic of the lower Portage beds in the vicin­ thickness nearly doubles in passing under the Allegheny 22. Shale ______... ______28 6 21. Sandstone______...._____:_____ 6 ity of Naples, Ontario County, N. Y., and taken in connection Plateau, for the Brallier is 1,800 feet thick where it emerges 20. Shale, with thin sandstone layers ______4 6 with the absence of any distinctively Genesee fossils justifies on the foothills of the Allegheny Front. South west ward along 19. Sandstone, with shale partings.....__..___ 1 4 the assignment of the Harrell shale to the Portage group. It the Appalachian Valley the Brallier can be traced into the IS.'.Shale . .____._.___ __..___:______1 7 17. Sandstone___..______1 6 probably represents in the main the Cashaqua and Middlesex Woodmont shale member of the Jennings formation in Mary­ 16. Shale...,____.._.______19 shale members of the Portage formation of New York and the land and into the Kimberling shale of southwestern Virginia, 15. Sandstone ______._,.__.. 9 14. Shale ______4 6 fossiliferous beds at Naples. The soft gray shale is almost which reaches a thickness of about 3,000 feet in Bland County. 13. Sandstone.:..______6 identical lithologically with the Cashaqua. The Burket mem­ The small fossils of the Naples fauna are present in the Wood­ .12. Shale ______..____ 25 ber is probably equivalent to the so-called Genesee shale of the mont as in the Brallier, and they occur as far southwest as 11. Shale, with sandstone bands ______4 6 10. Shale _____.______...______..______._._ . 52 7 Maryland Geological Survey report on the Devonian of Roanoke and Craig Counties, Va., but have not been found in 9. Sandstone ______3 Maryland, 1913. Bland County and farther southwest, where, however, the litho­ 8. Shale____..______.___.____ 6 7. Sandstone_..______8 BRALLIER SHALE logic character of the Brallier is well preserved and a few of 6. Shale______..___.._...______19 the problematic worm trails are found and plant shreds are 5. Shale and thin sandstone______.___._ 36 Name and definition. The Brallier shale was named for rather common. 4. Not exposed ______200db its exposures at Brallier, 5 miles northeast of Everett, Pa. It 3. Shale, with thin sandstone bands ______20 The fossils of the thin sandstone near Upper Reese mentioned is the upper formation of the Portage group of this region and 2. Sandstone, with Leiorhynchus mexacos- above probably indicate a brief invasion of the Ithaca fauna of tale and Productella speciosa f; bottom lies above the Harrell shale and below7 the Chemung formation. of Chemung ______2 the Portage which barely reached this area. Possibly the red The bottom of the Brallier shale is sharply marked, but at the beds mentioned above represent an extension of the Oneonta 2.953 10 top the Brallier merges into the succeeding Chemung, although sandstone, also of the Portage, into this region. Brallier shale: the two formations are easily distinguishable not far below or 1. Shale, greenish.. 20 above the boundary, which is fixed by the writer at the hori­ CHEMUXG FORMATION No. 68 and part of No. 67 are exposed on the New Portage zon at which the lowest Chemung fossils are found. The Chemung formation was named for its exposures along branch of the Pennsylvania Railroad in Blair Gap Run, half a Distribution. The formation crops out in a belt 1 to 1^ the Chemung River, N. Y. In these quadrangles it is under­ mile east of the quadrangle boundary, as follows: miles wide on the lower slope of the foothills of the Allegheny lain by the Brallier shale and overlain by the Hampshire forma­ Front, extending from Altoona to the southwest corner of the tion. The Chemung and Brallier are not separable by an 2. Section in Blair Gap Run Feet Hollidaysburg quadrangle, in a circular area in the center of easily recognizable lithologic difference at the contact, but the Hampshire formation (shale and sandstone, nearly all red). the Scotch Valley syncline, and east of Tussey Mountain separation is made at the lowest horizon at which locally fossils Chemung formation: along a broad belt half a mile to 1 mile wide, marked by Mudrock, yellow-green, lumpy and sandy; contains of the Chemung appear in the beds. Such fossils are Caron- Cyrtospirifer disjunctus and Camarotoechia sp.__ 50 Middle Ridge and the northern part of Piney Ridge. Good iferella lioga, Leiorhynclius mesacostale, Productella speciosa, Shale, yellow-green, with a few thin layers of fine­ exposures are to be seen on the Pennsylvania Railroad just Cyrtospirifer disjunctus, Leptodesma rogersi, and L. longispinum. grained green argillaceous sandstone, and a bed of chocolate-colored shale and sandstone 3 feet thick, west of Altoona and just east of Huntingdon. The use of this criterion has given consistent results in tracing 70 feet below the top; fossils scarce; fish fragments in Character. The Brallier is predominantly a pale greenish- the boundary. Not far above or below the boundary thus the chocolate-colored sandstone; Cyrtospirifer dis­ gray micaceous, sandy, and slaty shale, generally cleaving junctus and Camarotoechia sp. noted at one horizon 200 located the respective formations are recognizable by their Not exposed to bottom of No. 67 ___...__.______385 easily into thin laminae, but there are thin layers of coarser lithologic characteristics. texture and less perfect cleavage. In railroad cuts half a mile .Distribution.. There are three belts of outcrop one on the On the Portage branch of the Pennsylvania Railroad the east of Huntingdon very evenly bedded layers 1 to 2 feet foothills of the Allegheny Front, one in Raystown Valley, and rocks in interval No. 50 are partly exposed as follows: thick appear,in their unweathered condition, to be fine-grained a third east of Sideling Hill, in the southeast corner of the 3. /Section on .Portage branch of Pennsylvania Railroad

compact sandstone (pi. 20), but on weathering these beds reveal Huntingdon quadrangle. Feet their thin lamination cleavage and ultimately break down to Character. The Chemung is composed mostly of shale, but Shale and sandstone ______-__^______180 Not exposed______.. __ __,______90 small, thin plates. The rock is really a stiff sandy shale. A it includes considerable sandstone, generally in relatively thin Sandstone, thick bedded, fine grained; contains Spirifer striking feature of some of this shale is a strong dimpling of the layers interspersed through the shale, and a little conglomerate. mesistrialis (Saxton conglomerate member) _____.____ 10 bedding planes. In the upper 200 feet are layers of fine-grained (See pi. 21.) In general its lower part differs from the under­ Observations at other points warrant the statement that the greenish sandstone, becoming light gray or dirty white 'on lying Brallier shale in that its shale is prevailingly soft and gaps in section No. 1 are filled by rocks of the same character weathering, fragments of which in places strew the surface. of more clayey composition, or more of the nature of mudrock, as those exposed and that the section adequately represents the There are a few layers of evenly bedded sandstone and some and in that a greater number of thin sandstone layers are present. general character of the Chemung formation along the eastern thin, irregular layers of hard bluish fine-grained sandstone, Its character is illustrated by the following detailed sections: slope of the Allegheny Front. The following sections exhibit generally from 1 to 6 inches and rarely 1 foot thick, which are 1. Section of Chemung formation on main line of Pennsylvania Railroad its character in the Raystown Valley: more common from 100 to 200 feet above the base of the for­ beginning about 1_- miles east of Kittanning Point 4:. Section of upper part of Chemung formation at Hawn Bridge mation. Probably the formation does not contain more than Ft. in. 5 percent of layers of sufficient coherence to yield fragments Hampshire formation (shale and sandstone, Ft. in. almost all red). Hampshire formation (nearly all red for 2,000 feet). 6 inches thick on weathering. In one of the railroad cuts about Chemung formation: Chemung formation: a mile southwest of Altoona there are a few thin layers of 68. Shale and sandstone, yellow-green; 26. Not exposed; debris on surface indicates green pale-red shale, probably somewhat above the middle of the mudrock with thin sandstone layers; shale with thin layers of green sandstone as Cyrtospirifer disjunctus______. 85 in other sections. _.-.-___-___--______100 formation. A layer of red rock about a foot thick is exposed 67. Not exposed (see description below)._____ 600 25. Not exposed; red soil, with a few thin expo­ in the cut on the old incline just west of Foot of Ten. 66. Shale, chocolate-colored, with thin layers sures of red or chocolate-colored shale and of sandstone ______80 brown, sandstone, fossils in lower part_____ 380 Thickness. The thickness of the Brallier is about 1,800 feet. 65. Sandstone, few small pebbles__ ..._-___._ 2 24. Not exposed; green shale and sandstone Age and correlation. The Brallier is very sparsely fossil­ 64. Shal e, greenish gray, clay _ 35 debris ______-______70 iferous. The most common fossil is Pteridichnites biseriatus 63. Shale, with thin sandstone layers ______15 28. Partly exposed; green shale showing at in­ 62. Sandibtone. solid layer. ______2 tervals______: 35 Swartz, a slender, stemlike form about one-eighth of an inch 61. Shale and thin sandstone______6 22. Not exposed; gray soil, green shale and sand­ wide, commonly slightly curved, plainly or obscurely seg­ 60. Sandstone, thick bedded____..___.__. _ stone debris______--..-_-__.____ 80 59. Shale, blue, clay______...______21. Not exposed ______. __.__.__ 60 mented, with a narrow longitudinal depression along the 58. Conglomerate; pebbles half an inch in 20. Sandstone, laminated, cross-bedded, some middle. These suggest worm trails. They are rather com­ maximum diameter...______1 layers conglomeratic. _'______._..___..____ 20 mon in a green highly siliceous shale or laminated fine-grained 57. Sandstone, thick bedded ___._.______10 19. Partly exposed, shale and sandstone, choco­ 56. Shale, green, clay ---__--_ -----__- 30 late-colored and green._____..._____ 80 sandstone that, except in a few places, is without other organic 55. Shale and thin sandstone, gray ______30 18. Shale, with thin sandstone layers, mostly remains, and hence they are useful in identifying the forma­ 54. Shale, chocolate-colored:__._._ .______5 chocolate-colored____^______70 . 58. Shale and thin sandstone, gray ^ ______35 17. Sandstone, thick bedded, chocolate-colored; tion. A few of the small fossils of the Naples fauna range up 52. Shale and thin sandstone, with chocolate- containing uSpirifer" mesistrialis_____ 8 6 through the Brallier, as Buchiola retrostriata, Ontaria subor- colored layers___-_.___..____- __ 30 16. Sandstone, gray, cross-bedded, conglomeratic; bioularis, 0. aceindaf, Palaeoneilo peiila, and Plerocliaenia. 51. Shale, yellow:green______10 :' '.. contains bryozoans______2 6 50. Not exposed (see description below) ______400 15. Shale, with thin sandstone layers, chocolate- A species of Manticoeeras, Probeloceras lutheri, and rare 49. Sandstone, thick bedded, medium coarse colored ; contains bryozoans______10 specimens of Phragmostoma natator and of Pleurotomaria grained, gray, with ^tSpirifer"1' mesi&tri- 14. Shale, with thin sandstone layers, chocolate- alis (Saxton conglomerate member)--__ 10 colored ______- --__ 50 genundewa occur also. In contrast to the general rule a thin 48. Shale, soft clay ______. __ _ 10 13. Sandstone, chocolate-colored, hard, fine sandstone cropping out in the road about a quarter of a mile 47. Sandstone ______- ______10 grained, two layers of 3 feet each______6 northwest of Upper Reese is crowded with larger fossils, such as 46. Shale, blue clay, soft ____..______10 12. Shale, chocolate-colored _____ 10 45. Sandstone ______^_-______5 11. Sandstone, greenish, hard, fine grained, upper Cladoclmus humilis (rare), Productella speciosa, two other 44. Conglomerate______.__ -_-__ 3 feet solid, lower 3 feet in three layers, peb­ species of Productella, Chonetes cf. C. scitulus, Camarotoechia 43. Sandstone______.__- 15 bles in pockets _____-___ __ 6 42. Limestone, impure; fossils.__...______. (Nos. 11 to 17 inclusive may be the Saxton con­ cf. C. congregata, C. cf. C.sappho, "Spirifer"'c£.'S.mucronatus 41. Shale, with sandstone layers, 2 to 3 glomerate in two benches.) var. posterns and Ambocoelia umbonata. inches thick ____..-___- _____-_-______5 10. Shale and thin sandstone, chocolate-colored __ 250 In correlating the Brallier it should be noted that the sur­ 40. Shale, clay. ___.____-______15 9. Sandstone, greenish, fine grained, thick layers, 39. Sandstone, cross-bedded; has fucoids in tending to be laminated______15 vivors of the Naples fauna named are listed b}7 Clarke * 5 from bottom _____-____-_ ---_ _--- 10 8. Shale and thin sandstone, chocolate-colored __ 100 all the members above the Rhinestreet shale member in the 38. Shale, clay. _.-._- - .__.. .. 10 7. Shale, greenish. ______: 25 37. Sandstone._,______10 6. Sandstone, hard, fine grained, 1-foot layers 5 Portage Gorge section of New York. Even the occurrence of 36. Shale, clay ______-._ 25 5. Shale, mostly green ______75 the plant fragments is noted. Likewise these upper members 35. Shale, soft, dark and yellowish green, 4. Shale and sandstone, chocolate-colored ______20 of the Portage, and especially the Gardeau shale, the thickest with sandstone layers _____..__ _ _ 280 3. Not exposed; section south of Ha,wn Bridge 34. Not exposed _____,______- ______265 shows green shale and thin sand stone. __ _ 280 J 5 Clarke, J. M., and Luther, D. I)., Geologic map and descriptions of 33. Shale, gray and yellowish, with thin sand­ 2. Shale and thin sandstone flags, about one- the Portage and Nunda quadrangles: New York State Mns. Bull. 118, stone layers____-_-_- . _.__. __ 165 half each of chocolate-colored and green (see ['pj>.:57* 60, 61, 66, 1903. 32. Shale_l-_l _ - r _'T - --- 10 pi. 21)______..__ ..-_-_____-- 140 HoUidaysVnirg-Htmtingdoii 12

Ft. In this section the lower 810 feet is Brallier shale, and the Ft. 1. Shale and a few 4-inch sandstone layers; thin 28. Shale, green, stiff, fissile______10 impure shell limestone at base; shale fossils of No. 3 mark the Portage-Chemung boundary. Here, 27. Conglomerate, greenish gray, two or three mottled with purple______-____.______140 as at other points in the area, they occur in rather soft greenish thin layers of purplish gray, whole mass pebbly, some layers crowded with peb­ 1,938 clay shale 130 feet below the Piney Ridge sandstone member. bles half an inch in diameter, some The bottom of this section is near the horizon of the Alle- Some features of the preceding sections require comment. pebbles 1-J- inches long and half an inch One of these is the reddish shale and sandstone in the upper thick. Most of the pebbles are very grippis sandstone member, which does not show here and small, and in some layers these are probably is locally absent, for it shows well within half a mile half. This color has been described as red without recognition scattered _.__.______-_1_ of the fact that, almost without exception, the "red" color below 26. Shale, green, soft, and thin sandstone ___ _ both north and south of Hawn Bridge. 25. Sandstone, bluish, hard; iron stained on The above section is partly duplicated and partly supple­ the top of the Chemung is brown or chocolate-colored and weathering, contains fossils_.______mented by the following section along Raystown Branch and is noticeably different from the brighter hues prevailing in the 24. Sandstone, irregularly bedded, 2-inch lay­ Hampshire formation. It does not yield a red soil. ers, fine grained, greenish, in part more the Huntingdon & Broad Top Mountain Railroad northwest or less crumbly, about half sandstone of Saxton, 2 miles south of the southeast corner of the Holli- The green shale is mostly of clay composition, greenish to and half sandy shale; fossils _____ ...____' 6 bluish gray or slate-colored when fresh but weathering yellow- 23. Sandstone, like No. 27 but no pebbles ... __ 7 daysburg quadrangle. Sandstone, thin irregular flags, chocolate- The distance between No. 17 and the base of the Hampshire green. A little of this shale showing in the Pennsylvania colored ______5 in this section is 845 feet. No. 49 of the Pennsylvania Rail­ Railroad section on Burgoon Run is of rather bright greenish- 21. Shale, green, crumbly, ferruginous; fossils gray (copperas) color. 2£ feet below the top ______11 road section is 1,336 feet below the Hampshire in that area. 20. Sandstone, green, fine grained, flaggy _____ 3 If Nos. 17 and 49 are the same it appears that the base of the The sandstone, which except in a few places is present as thin 19. Shale, green, finely fissile ______layers in the shale, composing a small proportion of the whole, 18. Shale, chocolate-colored______Hampshire is 491 feet lower in the section at Hawn Bridge 17. Shale and thin sandstone, mainly choco­ than in the section on the Allegheny Front. This is in accord is almost all hard, tine grained, and either greenish gray or in late-colored______with the general observation that the red sediments transgress the upper part chocolate-brown. (See pi. 21.) There are some 16. Conglomerate, irregular lens; pebbles as much as 1 inch in diameter ______downward toward the east. thicker masses of sandstone, most of which is included in the sandstone or conglomeratic members described below. A very 102 5. Section of lower and middle part* of Chemung formation northwest of Saxton little impure limestone is formed by the accumulation of many Beds below Saxton member: Ft. in. shells in a few layers. The yellow-green lumpy mudrock and 15. Shale, green______3 45. Shale, green_....______40 14. Shale and sandstone; shale merges below Saxton conglomerate member: thin, irregularly surfaced fine-grained yellow or dark-greenish into sandstone, chocolate-colored _____ 8 44. Conglomerate ______7 sandstone at the top of the formation, as shown in section No. 13. Shale, chocolate-colored______4 12. Sandstone, green, fine grained; fossils at 43. Shale, green_. ______8 2, are highly characteristic and are invariably present just below 42. Sandstone __...... ______1 top, plant stems, Fenestrelina f, Camaro- 41. Shale, chocolate-colored__...... ___._.._____..._. 8 the red shales of the Hampshire throughout these quadrangles, toechia-.. ______40. Sandstone, chocolate-colored ______6 in the Ebensburg quadrangle, on the west, and as far northeast 11. Shale, chocolate-colored______89. Shall-', mostly green, chocolate-colored layer 10. Shale or mudrock, irregular, lumpy, green, 2 feet thick______.______...__.__ 16 as Lock Haven, Clinton County. They also carry everywhere, sandy, fine pebbles; fish scales?______3 88. Sandstone, thick bedded and conglomeratic _ 7 except possibly east of Sideling Hill, a peculiar assemblage of 9. Shale, lumpy, chocolate-colored______15 37. Shale, green ______.______._ 5 fossils, consisting of Cyrtospirifer disjunctus and a large coarse- 8. Shale, green; 1 foot of sandstone in middle 5 38. Sandstone, thick bedded, fine grained, choco­ 7. Shale and stiff layers (sandstone?), choco- late-colored ______15 ribbed Camarotoechia, and in the western outcrop a peculiar late-colored______20 35. Shale, green ______2 staple-shaped form described by H. S. Williams as Arenicolites. 6. Shale, chocolate-colored and green inter 34. Sandstone ______5 bedded; fossils in middle______._ 10 33. Shale, green ______30 The formation is moderately fossiliferous throughout and differs 5. Shale with 4-inch sandstone layers, choco­ 32. Sandstone, gray, flaggy ______..__ 3 greatly in that respect from the Chemung of western New late-colored______2 4. Not exposed; probably chocolate-colored 31. Sandstone, thick bedded, hard, fine grained _ 8 York. Such features as ripple marks, sun cracks, and rain 30. Shale, green .____.___.__.______20 shale______.__ 20 29. Not exposed; green and chocolate-colored shale prints are not common. 3. Sandstone, chocolate-colored, line grained 7 debris.. _.....______.._.._.______350 Thickness. The thickness of the formation is about 2,400 2. Sandstone, greenish and chocolate-colored, 28. Shale, green, thin, argillaceous, micaceous, with fine grained______15 green sandstone layers ______20 feet in its western area and 3,350 feet in the Raystown 1. Not exposed; chocolate-colored shale 27. Sandstone, fine grained, shale partings, chocolate- Valley. The measured section at Hawn Bridge shows 1,900 debris ______50± colored ____._...... ___..______..______-_ 65 feet down to the horizon of the Allegrippis sandstone, which is 163 2 26. Not exposed ______..__.. 250 25. Shale, green mudrock mottled with chocolate about 1,600 feet above the bottom of the Chemung, making a White refers to the Saxton (his Lackawaxen) only the 21 color; fossiliferous layer 75 feet below top______100 total of 3,500 feet. A measurement based on the average dip 24. Not exposed; thin sandstone d6bris______-__- 100 feet of No. 27, which may or may not persist as the most 23. Sandstone and fine-grained flags and shale, green 55 and the width of outcrop on Shy Beaver Creek is 3,300 feet. prominent bed in the member, so it seems best to include the 22. Limestone, crinoidal-_-___-______.--_--______--__ l_f East of Sideling Hill the thickness is about 2,800 to 3,000 full thickness of 102 feet in the member. The siliceous beds 21. Shale, mostljr chocolate-colored, green shale and feet. thin green sandstone at top, thick bedded, fine are hard fine-grained gray, greenish-gray, and chocolate-colored grained______.. __..______.._....______65 Piney Ridge sandstone member. The Piney Ridge sandstone sandstone, some containing scattered small pebbles and locally Allegrippis Sandstone member: was named for Piney Ridge, in the southern part of the 20. Sandstone, 2-foot shale parting in middle, crowded with quartz pebbles that make 50 per cent or more of ripple marked below shale. ______15 Huntingdon quadrangle, along which it crops out. It is a per­ the mass. The pebbles may be of clear glassy quartz, milky 19. Shale, green, ripple marked__.__.______--__. 15 sistent bed about 50 feet thick and is 30 to 200 feet above the quartz, or rose quartz, and the largest are !-§- inches in longest 18. Sandstone, like No. 20______. ____..______-___,_ 5 base of the Chemung. It is greenish gray and iron specked 17. Shale, gray, soft_____.______40 diameter. They are rather flat but not so flat as those of the 16. Sandstone, as above. ....___.__._____.____--__-- 2 6 and weathers with a white to light-gray surface. In the section conglomerates of western New York. White found fish frag­ 15. Shale, like No. 17 with blocky sandstone layers 8 northwest of Saxton (No. 5), it is made up of a number of rather inches or less thick ______100 ments in the conglomerate or associated layers, and the fact 14. Sandstone, fine-grained, in layers 1 to 6 inches thick sandstone layers, separated by soft greenish clay shale. that the Lackawaxen conglomerate of Pike County likewise thick, mostly chocolate colored; a little green In places fossils, of which there are several species, are fairly shale and sandstone _____..._____. ______160 has such remains is one reason for the correlation made by 13. Shale, green, stiff; thin sandstone layers.______30 abundant. White. 12. Shale, chocolate-colored______6 Allegrippis sandstone member. The Allegrippis sandstone The Saxton conglomerate member is all exposed in the 11. Shale and thin sandstone layers.______...... ___ was named for Allegrippis Ridge, which it forms and along 10. Not exposed. __. _____ .__...______river bluff 1,000 feet east of the northwest end of the railroad 9. Shale, green clay; even sandstone layers 6 inches which it crops out across the Huntington quadrangle. It is bridge over Raystown Branch at Saxton (section 5) and is or less thick ______..-______.__--- 150 about 1,400 feet above the Piney Ridge sandstone. It is gen­ excellently displayed in the river bed, where it makes a fall, on 8. Not exposed ______69 erally a greenish-gray sandstone, weathering white, but locally 7. Shale, green ______40 the Cove-Saxton road a quarter of a mile south of the Hunt­ 6. Sandstone and shale; sandstone irregularly is a coarse conglomerate and commonly has layers or pockets of ingdon quadrangle and in the river bank just south of the bedded ______..._____-______-_ 48 conglomeratic sandstone. As shown in section 5 there are three 5. Sandstone, flaggy, irregularly bedded; Piney quadrangle on the Saxton-Entriken Bridge road. It yields Ridge sandstone member (.)...... _ .______. 40 beds of sandstone, separated by shale, in a thickness of 77 the great quantity of large boulders at the foot of the bluff on 4. Shale, yellow, green, soft-__--..-_...._ ._---____---.-- 50 feet. Only for a short distance on Allegrippis Ridge near the the road 1 mile southwest of Entriken Bridge. It is well 3. Not exposed _.._-_-____..__..-___.-_--_____-___-----_- 50 south boundary of the Huntingdon quadrangle was coarse 2. Mudrock, stiff ______.__..______5 exposed on the road midway between Grafton and Fink Bridge 1. Shale and thin sandstone, near bottom of Che­ conglomerate observed. mung. ______85 where White reports pebbles 3 inches in longest diameter. It Saxton conglomerate member. The Saxton conglomerate is also clearly exposed in the bluff north of Hawn Bridge but 2,232 li member was named for Saxton, 2 miles south of the Hunting­ is neither heavy nor very conglomeratic at that point nor If this section goes to the bottom of the Chemung, as it don quadrangle, where it is well exposed. It is the Lackawaxen farther north. appears, and if the sandstone of No. 5 is the Piney Ridge conglomerate of I. C. White, who correlated it with a conglom­ The conglomerate mapped in the western area of Chemung sandstone member, there is probably a fault between it and the erate so named by him from Lackawaxen Township, Pike in the Hollidaysburg quadrangle is believed to be the Saxton, Allegrippis sandstone, for farther north the interval between County, Pa. As a conglomerate supposed to be the Lackawaxen partly because the western conglomerate is about the same the two is 1,400 feet, whereas in this section it is only 800 feet. had been reported from only one intermediate point, there distance below the top of the Chemung as the Saxton and partly seemed sufficient doubt about the correlation to warrant the 6. Section along Pennsylvania Railroad from Huntingdon to Ardenheim because of the presence of "Spirifer" mesistrialis in the bed in adoption of a new name. both areas. It is best exhibited in that area in a cut on the [Top is about half a mile west of Ardenheim] The Saxton conglomerate is made up of conglomeratic sand­ Pennsylvania Railroad as shown in section 1 and may be traced Chemung formation; Feet stone and shale of greenish, greenish-gray, and chocolate-brown 15. Sandstone, thick bedded __....___. ....___.____ 10 by its debris southwestward along the line of high knobs nearly 14. Shale ______15 hues as shown in the preceding sections of the Chemung and to the southwest corner of the Hollidaysburg quadrangle. 13. Sandstone, thick bedded______5 in the following section measured on Raystown Branch a few Other conglomerates. There are at least three other local 12. Shale, yellow-green clay______15 hundred feet south of the south line of the Huntingdon quad­ 11. Sandstone, thick bedded. ..__-__-___.____-______10 conglomerates present in the Chemung formation of this area. 10. Shale, yellow-greeii______.-_-____-____-. ._. 65 rangle : One is about 20 feet thick and about 400 feet below the 9. Not exposed ______._-__.___ 50 8. Shale, yellow-green. ______..______..____-__.... 80 Section of the Saxton conglomerate member southeast of Cove station on Allegrippis sandstone half a mile west of Hawn Bridge. A 7. Shale yellow green with many sandstone layers 1 Raystown Branch conglomerate about 1 foot thick in the Shy Beaver Creek to 6 inches thick.______120 Chemung formation: Ft, in. section probably lies at this horizon. In the Hawn Bridge 6. Sandstone, with shale partings (Piney Ridpe?) ______50 Saxton conglomerate member: 5. Shale ______.___-.______. ..-.....____ 100 32. Sandstone, chocolate-colored, cross-bedded section (No. 4), bed 20 is a 25-foot bed of conglomeratic sand­ 4. Sandstone, with shale partings______.__. 30 at bottom, with pebbles 1 foot above stone about 100 feet above the Saxton conglomerate- member. 3. Shale, soft clay, fossils (Leptodesma) near top.__...._ 160 bottom ____..______3 BralHer shale: 31. Conglomerate, ferruginous, quartz pebbles A mile west of Fink Bridge a second conglomeratic sandstone 2. Not exposed..______. 160 three-quarters of' an inch in diameter, __ 1 8 about 500 feet above the Saxton conglomerate is indicated by 1. Shale, stiff, green, siliceous and mica.ceous; some 30. Shale, green, rather fissile.-______13 de'bris. In the western area of the Chemung is a conglomeratic freshly exposed portions resemble sandstone 29. Sandstone, fine grained, ferruginous in top (pi. 20) but weather to shaly chips; typical____.. 650 6 feet, bluish in bottom foot ______7 sandstone showing on the Pennsylvania Railroad (section 1) 13

540 feet above the Saxton that probably represents this upper gray and greenish beds 500 feet above the bottom and 500 feet Burgoon sandstone member. The Burgoon sandstone was conglomerate horizon. below the top, among which are Cyrlospirifer disjunclus, Dellhy- named for Burgoon Run, in the northwest corner of the Holli­ Age and correlation. The Chemung is fossiliferous through­ ris mesacostalis, Schucliertella ckemungensis, Qrammysia elliptica, daysburg quadrangle. It consists of nearly continuous thick- out, The 111 species collected include those most character­ Sphenotus clavulus, and Pteronites rostratus. 0 elder tellapleur ties bedded, rather coarse micaceous and feldspathic sandstone, istic of the Chemung of the type locality in western New York, was found near the bottom of the formation. yellowish green to bluish gray, and weathering gray. On the and the Chemung age of the fauna is unquestionable. Some of The Hampshire west of the Broadtop Mountain syncline is Allegheny Front it contains locally at one horizon or another the species are cited in the detailed stratigraphic sections. known through tracing and well borings to include the equiva­ small quartz pebbles but is nowhere conspicuously conglomeratic. Gliemung-Hampshire boundary. White 16 drew the bound­ lent of strata in western New York and northwestern Pennsyl­ On the Allegheny Front it is 300 feet thick and on Terrace ary between the Chemung and Catskill (Hampshire of this vania that are characterized by beds of red shale. These western Mountain at least 375 feet and may be as much as 500 feet. report) at the bottom of the lowest chocolate-colored ("red") strata have usually been classed as Devonian and are still so Coal in the Pocono. On the Allegheny Front nn 8-inch coal layers, which he placed 150 feet above the Allegrippis sandstone. classed by good authorities. There are, however, considerations, bed in the Burgoon sandstone, about 100 feet above the bottom, He had approached the region from eastern Pennsylvania, not necessary to discuss here, favoring the conclusion that they is exposed on the Pennsylvania Railroad. I. C. White reports where the redbeds facies extends much lower stratigraphically are really Carboniferous, and they are so classed by the New thin streaks of coal apparently near the same horizon, exposed than it does in the central and northwestern parts of the State. York State Geological Survey. 20 in the gorge of Great Trough Creek. Ashburner reports 19 thin Stevenson, 17 however, approaching the region from the west, layers of coal in the Pocono of Sideling Hill, exposed in the tun­ placed the Chemung-Catskill boundary at the base of the con­ CARBONIFEROUS SYSTEM nel of the East Broad Top Railroad 5 miles south of the Hunt­ tinuous redbeds, thus including in the Chemung all the The rocks of unquestioned Carboniferous age in this region ingdon quadrangle. No coal of commercial value is known in distinctly marine fossiliferous beds. The writer adopts this are divided into the Mississippian series below and the Pennsyl- this formation. boundary, which gives a constant and consistent division plane vanian series, or coal measures, above. The Mississippian series Thickness. On the Allegheny Front the total thickness of valid for Pennsylvania west of the Broadtop Mountain syncline. is subdivided into the Pocono, Loyalhanna, and Mauch Chunk the Pocono is 990 feet; on Terrace Mountain and Sideling Hill East of Sideling Hill, however, the redbeds of Catskill type formations, and the Pennsylvanian series into the Potlsville, it is 1,400 feet, Ashburner 21 made the thickness of the extend lower and probably include the equivalent of 500 to 700 Allegheny, Conemaugh, and Monongahela formations, but the Pocono in Sideling Hill 2,133 feet, but this seems to be errone­ feet of rocks that are embraced in the Chemung west of the last two are not present in the Hollidaysburg and Huntingdon ous, for the thickness cannot exceed the width of outcrop, which Broadtop Mountain syncline, for apparently Chemung fossils quadrangles. is only 1,400 feet. do not extend more than 300 feet above the Saxton conglom­ MISSISSIPPIAN SERIES Age and correlation. The lower part of the Pocono is some­ erate member in that part of the area, whereas they are abundant what fossiliferous, yielding both plant and animal fossils,includ­ POCONO FORMATION for 1,300 feet above on the Allegheny Front. It appears that ing the undescribed calcareous algae mentioned above. the Chemiuig-Hampshire boundary will have to be located at Name and definition. The Pocono formation was named David White refers the beds below the Burgoon sandstone lower and lower horizons eastward from the Broadtop Mountain from its development in the Pocono Mountains of northeastern carrying lepidodendrons to the Mississippian but with a reser­ svncline. Pennsylvania. In the Hollidaysburg-Huntingdon area the vation on beds containing Lepidodendron chemungemef* Those HAMPSHIRE FORMATION Pocono includes all the rocks, predominantly gray, between the beds, however, are Mississippian if the others are. red Hampshire below and the equally red Mauch Chunk above. The lower division of the Pocono carries invertebrates in the Name and definition. The Hampshire formation was named It is sharply distinguished from both and easily recognized. Broadtop Mountain and Terrace Mountain areain a bed of shale by Darton 18 from Hampshire County, W. Va. It was applied The bottom contact is exposed on the Pennsylvania Railroad 50 feet thick 600 feet below the top. Girty 22 has studied to the youngest Devonian formation in the central Appalachian on the Allegheny Front. (See pi. 22.) these fossils and finds that they are all new species bearing region of Virginia and West Virginia. The beds here called The basal 50 feet of the Pocono is marked over a large area more resemblance to those of a Cuyahoga horizon in Ohio than Hampshire were at one time referred to the Catskill formation, in central Pennsylvania by one or more layers of a ferrugi­ any others. but recent investigations have shown that the rocks in the nous and calcareous conglomerate, which in places carries many Independently of evidence from fossils the Burgoon sandstone Catskill Mountains are older than beds that have been referred small heads of a calcareous alga, the largest 2 inches in diameter. is satisfactorily correlated through field tracing and oil-well bor­ to the Catskill in Pennsylvania, West Virginia, and Virginia. Such layers were observed in the Riddlesburg Gap of the ings with the Logan formation of Ohio and the lower shaly (See fig. 5.) The use of the name Hampshire conforms with Juniata River, 3 miles south of the southwest corner of the part of the Pocono with the Cuyahoga formation of Ohio. It present usage of the Virginia Geological Survey. ] ° In this Huntingdon quadrangle; on the railroad 2 miles south of the is now known that the Logan and Cuyahoga are the equiva­ region the Hampshire formation overlies the Chemung and is Horseshoe Curve, on the Allegheny Front; on the Snowshoe lent of the New Providence shale of Indiana and Kentucky^ overlain by the Pocono formation. branch of the Pennsylvania Railroad half a mile northeast of and that the New Providence is the approximate equivalent of Distribution. The Hampshire crops out in a broad belt along Clarks station, in the Bellefonte quadrangle, Centre County; the Fern Glen and lower Burlington beds of Illinois, Iowa, and the west side of the Hollidaysburg quadrangle, and a great and 2 miles northwest of Lock Haven, Clinton County, in the Missouri, whence it follows that the Pocono is correlative with part of the formation is exposed in the railroad cuts east of east bluff of the river. At every one of these localities the the Fern .Glen and lower Burlington beds of the Mississippi Kittanning Point. Another belt 1 to 2 miles wide crosses the layers of algae appear within 50 feet above the continuous red­ Valley. Huntingdon quadrangle along Raystown Branch, whose beds of the Hampshire and are a reliable marker for the base meanders cut across the redbeds a number of times and lay HIATUS BETWEEN" THE POCONO FORMATION" AND LOYALHANNTA of the Pocono. LIMESTONE them bare. A third belt crosses the southeast corner of the Distribution. The Pocono crops out on the steep upper face Huntingdon quadrangle along Smith Valley, which lies On the Allegheny Front there is an unconformity at the top and caps the spurs and summits of the Allegheny Front in the of the Burgoon sandstone resulting from the absence of beds entirely upon the Hampshire outcrop. northwest corner of the Hollidaysburg quadrangle, where it is Character. The most obvious and distinctive feature of the equivalent to the Warsaw, Spergen, St. Louis, and Keokuk almost all exposed along the Pennsylvania Railroad in the gorge limestones. In the Broadtop Mountain region this uncon­ Hampshire is its red color. According to Eidgway's classifi­ of Sugar Run. In the Huntingdon quadrangle the Pocono crops formity is increased by the absence of the Loyalhanna limestone cation of colors, however, the Hampshire "red" ranges through out along the upper part of the west face of Terrace Mountain vinaceous drab, brownish drab, dsep brownish drab, and dark in addition. On the Allegheny Front the Loyalhanna succeeds and over a wide area on its gentle east slope known as The Bar­ the Burgoon, and in the Broadtop Mountain region the Mauch grayish brown, which result from mixture in different propor­ rens. The formation also crops out along Sideling Hill, the Chunk shale, which overlies the Loyalhanna, succeeds the tions of red and orange. In the area on the Allegheny Front core of which is formed by the vertical beds of the lower part Burgoon. probably 80 percent and in the Raystown Valley probably 95 of the Burgoon sandstone member. percent of the Hampshire rocks have one of these hues. The Character. On the Allegheny Front and on Terrace Moun­ LOYALHANNA LIMESTONE Hampshire, however, includes gray or greenish beds, rarely tain the Pocono includes two very distinct lithologic subdivisions Name and definition. The Loyalhanna limestone is the same exceeding 20 feet in thickness, of the same texture as the red- that make up the main mass of the formation. The upper main as the "Siliceous" limestone of the reports of the Second Geo­ beds. Streaks of greenish-gray rock 1 to 4 inches thick and subdivision is the Burgoon sandstone member. The lower main logical Survey of Pennsylvania. It was named for its exposures irregular mixtures or mottling of greenish gray in the "red" subdivision, constituting about two-thirds of the Pocono, is, on in the gorge of Loyalhanna Creek, above Latrobe, in West- layers are common and make very striking contrasts with the the Allegheny Front and probably on Terrace Mountain also, moreland County. It has been customary to include the prevailing "red." composed predominantly of gray sandy shale that includes beds Loyalhanna in the Pocono as a member, but for reasons stated It is estimated that the Hampshire is three-fourths shale and of gray and red sandstone, red shale, and some layers of clay. below it is now given the rank of a formation. It occupies the one-fourth sandstone. The shale is a coarse, lumpy mudrock. In Terrace Mountain a bed of conglomerate with quartz pebbles, stratigraphic interval above the Burgoon sandstone member of It is without fissility, breaks or crumbles into irregular lumps, the largest half an inch in diameter, occurs locally at least in the Pocono and below the Mauch Chunk formation. and passes by admixture of sand into a coarse, lumpy sand­ this division near the bottom. This bed is exposed in the gorge Distribution. The Loyalhanna limestone has only a small stone. The sandstone is generally fine grained and hard and of Great Trough Creek through Terrace Mountain and has con­ extent of outcrop on the summit of the Allegheny Front in the in layers 1 to 2 feet thick, but part of it is in layers only 1 to siderable extent in that region. On the Allegheny Front, as northwest corner of the Hollidaysburg quadrangle. It extends 2 inches thick. Some layers are thinly fissile and some highly exposed on the Pennsylvania Railroad, a bed of sandstone 180 westward throughout Westmoreland County into Fayette micaceous. Few of the sandstone strata exceed 50 feet in feet thick, including a layer of red shale 50 feet above the bot­ County and probably underlies all the southwestern counties thickness, and most of them are between 5 and 20 feet thick. tom, lies at the bottom of the Pocono and immediately upon the of Pennsylvania. Sun cracks and ripple marks are common, and there is some thick red shale that forms the top of the Hampshire. On Side­ Character. The Loyalhanna is a siliceous and slightly cross-bedding. ling Hill the exposures are poor and the two main subdivisions oolitic limestone of differing composition in different layers. Thickness. The thickness of the Hampshire is 2,000 feet west are not as obvious as elsewhere, but the upper part is a sandstone Some seem to be predominantly composed of quartz grains of the Broadtop trough and about 2,500 feet east of Sideling Hill. of the Burgoon type, and shale is exposed in the lower part at cemented by calcium carbonate, and others are predominantly Age and correlation. As stated above, the lower 500 one place. The two subdivisions are therefore indicated, but limestone with scattered quartz grains. It is notably cross- to 700 feet of the Hampshire east of Sideling Hill is believed their limits and thickress have not been determined. bedded, the cross-bedding being plainly revealed by diagonal to be contemporaneous with the upper 500 to 700 feet of the The thickness of the lower subdivision is about 700 feet on furrows on the weathered surfaces, some of which are also deeply Chemung west of the Broadtop Mountain syncline and therefore the Allegheny Front and 900 to 1,00.0 feet on Terrace Moun­ pitted owing to leaching of the more calcareous parts. (See to be of Chemung age. No fossils were found east of Tussey tain. pi. 23.) Mountain, nor are any known from the red parts of the formation Patton shale member. The Patton shale was named .for Pat- Thickness. The Loyalhanna limestone is about 40 feet thick anywhere, but in the Hollidaysburg area marine fossils occur in ton station, in Jefferson County. On the railroad along the in this region. "White, I. C., op. cit., p. 101. Allegheny Front it is a bed of red shale about 40 feet thick im­ Age and correlation. The Loyalhanna is lithologically much 17 Stevenson, J. J., The geology of Bedford and Fxilton Counties: Penn­ mediately underlying the Burgoon sandstone member. In the like the Ste. Genevieve limestone of northeastern Kentucky, sylvania Second Geol. Survey Rept. T2, p. 76, 1885. 18 Dartori, N. H., Notes on the stratigraphy of a portion of central region west of the Allegheny Front the Patton shale is a prom­ 2 Ashburner, C. A., Augliwick Valley and East Broad Top district: Appalachian Virginia: Am. Geol., vol. 10, pp. 13, 17, 18, 1892. inent horizon marker. Pennsylvania Second Geol. Survey Rept. F, pp. 206 208, 1878. 19 Butts, Charles, Geology of the Appalachian Valley in Virginia: Va. BS Girty, G. H., Pocono fauna of the Broadtop coal field, Pennsylvania: Geol. Survey. Bull. 52, pp. 333-335, 1940. 1 Hartnagel, C. A., New York State Mus. Handbook 19, 1912. U. S. Geol. Survey Prof. Paper 150, p. Ill, 1928. Hollidaysburg-Huntingclon which there is a siliceous cross-bedded oolite. In that region Trough Creek member: Ridge is 300 feet. This estimate agrees very closely with the the Ste. Genevieve immediately overlies the Logan formation 6. Limestone, red, breceiated, fossils (Straparollus), thickness of 280 feet determined by Ashburner. 2 5 His section and is succeeded above by the Gasper oolite. Now, as already 5. Shale, red, and limy beds______is as follows: 4. Limestone, gray______,.______shown, the Logan formation is the same as the Burgoon sand­ 3. Shale, red, and limy beds______._..______Section of Pottsville formation on Wrays Hill and RocJty Ridge stone immediately beneath the Loyalhaima limestone, and the 2. Limestone, gray_.-.______-.______Feet Gasper oolite, overlying the Ste. Genevieve in eastern Ken­ Pocono formation: Sandstone [Homewood?]-______160 1. Sandstone, gray, massive (Burgoon member)___ 20 tucky and the main constituent of the Maxville limestone of Shale [Mercer]______.. ______40 Sandstone [Connoquenessing]______10 Ohio, is correlated by its fossils with the Greenbrier limestone The Trough Creek limestone has been quarried and utilized Sandstone______..______70 to a considerable extent for agricultural lime, which is said to be member of the Mauch Chunk shale, 50 feet above the Loyal- 280 hanna limestone on Chestnut Ridge east of Connellsville and of excellent quality. Probably the lower 80 feet of sandstone is all Connoque­ elsewhere in southwestern Pennsylvania and western Maryland. Age and correlation. Except specimens of Straparollus nessing. On the basis of sequence and character, therefore, the Loyal- reported by White (see section No. 2 above) and of Dielasmiaf Age and correlation. It has been shown by White 2 6 that and Allorismaf reported by Ashburner from a quarry at Tod hanna is probably the eastern representative of the Ste. the Pottsville of this region corresponds to only the topmost Genevieve. and a few reported by Reger apparently from the same place, beds of the Pottsville along the east side of the Appalachian no fossils have been found in the Mauch Chunk of this region. MAUCH CHUNK FORMATION region. White divides the Pottsville into lower, middle, and In Westmorland County, however, on Chestnut Ridge, the upper divisions, and the Pottsville of this region includes only Mauch Chunk includes near the bottom the Greenbrier limestone Name and definition. The name Mauch Chunk is taken the upper three members of the upper Pottsville. Further from Mauch Chunk, in the anthracite region of eastern Penn­ member, which by its fossils is correlated with the Maxville discussion of this subject is given under "Historical geology." sylvania, where the formation is typically developed. It over­ limestone of Ohio. The Maxville is in the main equivalent to lies the Pocono formation and underlies the Pottsville, and in the Gasper oolite of Kentucky and Tennessee, which is of lower ALLEGHENY FORMATION the Huntingdon quadrangle it includes at or near the bottom Chester age. Possibly the Trough Creek limestone is a north­ Name and definition. The Allegheny formation was named the Trough Creek limestone member. westward extension of the Greenbrier and therefore of lower for the Allegheny Valley, where it is typically developed. It Distribution. The Mauch Chunk is present in the north­ Chester age, from which it follows that the usual correlation of was formerly known as the "Lower Productive Coal Measures." west corner of the Hollidaysburg quadrangle and on the slopes the Mauch Chunk with the Chester group, if the Ste* Genevieve It overlies the Pottsville formation and is the youngest Paleozoic of Broadtop Mountain in the Huntingdon quadrangle. The limestone is omitted, is amply justified. formation present in these quadrangles. formation is well exposed at many points in the Trough Creek HIATUS AT BASE OF POTTSVILLE FORMATION Distribution. Only a very small area of the Allegheny for­ Valley, and Hound Mountain is composed of it except a thin mation is present in the Hollidaysburg quadrangle, on the spur cap of Pottsville sandstone. In the anthracite field of eastern Pennsylvania the Mauch between Burgoon and Sugar Runs. In the southeast corner of Character. On the Allegheny Front, immediately above the Chunk is 2,200 feet thick; in the Broadtop region, 1,100 feet; the Huntingdon quadrangle there is a small area of the Alle­ Loyalhaima limestone, lies 5 to G feet of interbedded red shale on the Allegheny Front 180 feet; in the Allegheny Valley it is gheny on Rocky Ridge. and sandstone, and above this is 80 feet of mostly thick-bedded absent. This thinning and disappearance of the Mauch Chunk Character. The Allegheny formation consists of shale, sand­ gray to greenish sandstone, in the lower part of which occurs westward is regarded as probably due to its erosion after deposi­ stone, and limestone, with a number of coal beds. The coal a bed of conglomerate 2 to 3 feet thick. The character of these tion. It was upon the eroded surface of the Mauch Chunk that beds mined in Cambria and Clearfield Counties, west and north­ beds is shown in Plate 24. The sandstone is succeeded by the Pottsville of this region was deposited, so that an uncon­ west of the Hollidaysburg quadrangle, and those of Rocky shale, mostly red but with thin green layers. The red shale is formity exists between them. This relation between the Potts­ Ridge and Broadtop Mountain are in the Allegheny formation. soft, and some of it appears to be earthy. It is not fissile but ville and the Mississippian continues along the western part of Rocky Ridge contains three thick coal beds -the Fulton bed, crumbly and lumpy, and most of it weathers into small cubical the Appalachian province from New York to Alabama. 6 feet thick, close above the top of the Pottsville; the Barnett The hiatus between the Mauch Chunk and the Pottsville is fragments. bed, 3 feet G inches thick, 45 feet above the Fulton; and the In the Trough Creek Valley the Mauch Chunk is almost far greater than would appear from this simple statement. The Kelly bed, 4 feet 8 inches thick, 100 feet above the Barnett wholly a solid body of red shale similar to that on the Alle­ Pottsville that follows the Mauch Chunk in this region is and very near the top of the part of the Allegheny formation gheny Front. At or near the bottom in the Huntingdon quad­ late Pottsville, and along the Appalachian troughs, as in the present in that locality. The intervening beds are shale and rangle lies the Trough Creek, limestone member, and at the top Pocahontas coal field, in West Virginia, and the Coosa and sandstone, as in the Allegheny elsewhere. is a few feet of greenish flaggy sandstone and shale. Red sand­ Cahaba troughs, in Alabama, as much as 10,000 feet or even Thickness. On the Allegheny Front probably not more than stone debris at the south base of Round Mountain near New- more of still earlier Pottsville beds was laid down in the interval the basal 50 feet of the Allegheny is present, and the thickness burg and yellow-green sandstone debris 200 feet higher show represented by the Mauch Chunk-Pottsville unconformity. remaining on Rocky Ridge probably does not much exceed the presence of thin sandstone layers in the shale. Thin lime­ SERIES 200 feet. stone is reported near the middle of the red shale on Round Age and correlation. As implied in the name, the Alle­ POTTSVILLE FORMATION Mountain and near Newburg. No body of greenish and gray gheny formation of this region is the equivalent of the Alle­ thick-bedded sandstone is present in the Trough Creek Valley Name and definition. The Pottsville was named for its gheny formation west of the Allegheny Front. To judge from as on the Allegheny Front. As in the Hampshire, the "red" development at Pottsville, Pa. It overlies the Mauch Chunk their stratigraphic relations the Fulton coal is Clarion, the color is brownish or light brownish drab, according to Ridgway's formation and underlies the Allegheny formation and is here Baruett is Lower Kittanning, and the Kelly is Upper Freeport. color classification. composed of the Connoquenessing sandstone member, the LATE PALEOZOIC, MESOZOIC, AND TEBTIARY KOCKS The Mauch Chunk decomposes to a loose rich soil of good Mercer shale member, and the Homewood sandstone member, depth and free from stones, and its area in the Trough Creek the three members recognized in the western part of the State. Except the Recent deposits described below, no rocks Valley is one of the best farming districts in these quadrangles. Distribution. The Pottsville occupies a small area on the younger than those of the Allegheny formation still remain In the.forests its outcrop is marked by peculiarities of vegetation, margin of the plateau in the northwest corner of the Hollidays­ in the Hollidaysburg and Huntingdon quadrangles. An such as large straight trees and freedom from undergrowth of burg quadrangle. There is a rather extensive area on the north­ immensely long period of time, represented in other parts of brush and saplings, which grow thickly upon the adjoining ern margin of Eroadtop Mountain, two small areas capping the earth by tens of thousands of feet of rocks, is thus not Pottsville and Burgoon arear. Instead of underbrush there is Bunns and Round Mountains, and a triangular area on Rocky represented here. an abundance of herbaceous plants in a rather open forest, and Ridge extending from the quadrangle boundary north to the QUATERNARY SYSTEM in such a spot a stroke of the pick rarely fails to disclose the summit of Shirley Knob. Only on Rocky Ridge is the full characteristic red soil. This feature was utilized in tracing the thickness of the formation present in the Broadtop area. Alluvium. Under the head of alluvium are included the silt, outcrop along the wooded Allegheny Front. Character. The Counoquenessing member of the Pottsville sand, and gravel deposited on the flood plains of existing streams Thickness. The thickness of the Mauch Chunk on the Alle­ is a rather coarse gray sandstone, 80 to 100 feet thick, containing as they have overflowed their banks in Recent time. Such gheny Front is 180 feet, in Trough Creek Valley about 1,000 small lenses or layers of gray sandy shale. Above it on the deposits are probably nowhere in this region more than 25 feet. Pennsylvania Railroad just southeast of Bennington Station feet thick. Trough Creek limestone member. The Trough Creek lime­ lies 6 feet of shale, overlain by 9 feet of fire clay, at the top of STRUCTURE stone member, named by White 23 lies near the bottom of the which, partly included in the overlying Homewood sandstone, The Hollidaysburg and Huntingdon quadrangles are situated Mauch Chunk and is separated from the Burgoon sandstone are small pockets of coal 2 inches thick. In the shale were on the northwest side of the Valley and Ridge province and member of the Pocono by a few feet of red and green shale and found specimens of small plants, which are regarded by David participate in the main features of geologic structure character­ some thin layers of soft yellow-green sandstone. It is a rather White as characteristic of the Mercer shale, lying between the izing that province from southeastern New York to northeastern coarsely crystalline "red" and gray limestone, as shown in the Connoquenessing and Homewood sandstones of other areas, and Alabama. following sections. these beds are therefore identified as the Mercer shale member By structure is meant the present attitude of the strata, which 1. Section in the bend of Great Trough Creek a short distance northwest of the Pottsville. In the southwest corner of the Patton quad­ were deposited approximately horizontal but subsequently were of Tod rangle, about 2 miles north of Bennington, the Mercer coal is a Ft. in. tilted or folded and broken in places and displaced along the Mauch Chunk formation: workable bed, but it is not known to be workable in the Holli­ breaks (faulted). Instead of lying horizontal the strata are now 5. Shale, red, crumbly, with calcareous layers and daysburg quadrangle. The Homewood sandstone, at the top of nodules___.______25 generally inclined at different angles or even overturned in Trough Creek member (quarried): the Pottsville, is coarse, thick bedded, and 15 feet thick. It places. This structure is represented by dip and strike symbols 4. Limestone, thin layered, with red bands__ 8 shows well in the first cut east of Bennington but dips below on the geologic maps and by structure sections, which exhibit 3. Limestone, gray______3 2. Shale, like JN'o. 1, but no calcareous layers seen; track level 400 feet east of the station. Neither the Connoque­ the beds as they would appear on the side of a deep trench cut­ only partly exposed______6 nessing nor the Homewood sandstone is conglomeratic in this ting directly across the outcropping edges of the strata. ., . Pocono formation: section. 1. Sandstone, even top, cross-bedded (Burgoon The larger features of the structure are the two great folds member). In the Broadtop Mountain region the Pottsville is likewise that cross the region with a trend about N. 30° E. These are made up of two coarse siliceous sandstone members probably White says that a limestone 2 feet thick is exposed just above the Nittany arch on the northwest and the Broadtop trough on separated by shale, although no exposure of the shale is to be the Pocono in this section. the southeast. seen in that region. The sandstones are fairly well exposed on The Nittany arch is a great upbending of the strata, 35 miles 2. Section at the mouth of Lick Run, three-fourths of a mile east of Rocky Ridge and in the gorge of Great Trough Creek, in the Newburg ** wide, from the bottom of the Broadtop trough, in the southeast Ft. in. southeast corner of the Huntingdon quadrangle, but not in such corner of the Huntingdon quadrangle, on >the southeast to the Mauch Chunk formation: a condition that the thickness of either could be accurately bottom of the Wilmore syncline, 5 miles west of the northwest 7. Sh»ile, red.______determined. corner of the Hollidaysburg quadrangle, on the northwest. - 3 White, I. C., The geology of Huntingdon County: Pennsylvania 2d Thickness. The thickness of the Pottsville on the Allegheny Geol. Survey Kept, T3, p. 283, 1885. S5 Ashburner, C. A., op. cit., p. 192. 24 White, I. C., idem, p. 283. Front is 130 feet, and the best estimate of its thickness in Rocky S6 White, David, (Jeol. Soc. America Bull., vol. 15, pp. 267-282, 1904, 15

Figure 4 shows a section across the Mttany arch and Broadtop carora quartzite has undergone cementation to compact quartzite In Gatesburg time at least some parts of the land yielded syneline, made up by combining structure section F F' of the where the silicilication could have been effected by water that great quantities of quartz sand. A somewhat arid climate may Huntingdon quadrangle and section C-C' of the Hollidays- could easily penetrate the vertical beds cropping out on the have prevailed, resulting in concentrated saline water that favored burg quadrangle and restoring the strata that have been eroded summits of the high ridges. There is no apparent evidence of the deposition of a great thickness of coarse dolomite. There from the crest of the arch. The Allegheny formation, the high­ load metamorphism in the lowest beds exposed on the summit may have been intermittent floods, as in modern desert regions, est in the quadrangles, would on the restored arch be about 5 of the Nittany arch, where they were once subjected to a that carried the quartz sand to the sea to form the recurrent beds miles above the present surface of the land on the crest of the load of overlying rocks 5 miles thick and probably had a of sandstone. For a brief time limestone-forming conditions arch, the highest point of which lies about 1 mile northwest of temperature of not less than 300° F. prevailed locally, and the Ore Hill limestone member was laid down. Conditions were favorable to life in the Ore Hill sea, in -N/TTANY ARCH- -25,000' * I -BROAD TOP MOUNTAIN TROUGH- which lived trilobites and a few other forms. -5-1--. ~^>, yIk--,.--^'"" S B ^- ^ | -20,000' I \ i «-- r--^x. .Ji ORDOVICIAN PERIOD -15,000' I«) ::-f ,.==^4:::44^4^VVit- ^V * s. -IO.OOO' During most of the Ordovician period, limestone and dolomite ! /! - 5,000' were deposited in this region. Near the end of the period clastic <-pEHN^fl^M\^M-^_ _^ ^^''','-'''' 1^1 8 /'j;;;''\ \-\ %^v XX^^T|.- p- ^><=^ :^r^Z^-^-Jb^-^./l~^. \ \^-^-^g^__ ^fe Seer level sediment that now forms the Reedsville shale and tlie Juniata

- SfCQ- - -5,000' formation were deposited.

- lOflOtf- -10,000' At the beginning of Mines time the sea was briefly invaded

~\5,OQQ'- -15,000' in places by many gastropods. The general geographic and

-ZQfXXf- -20,000' climatic conditions of Gatesburg time continued, possibly with

-35,000'- -25,000' a still wider sea and less drainage, with resulting cessation of transportation of sand but with increase of disseminated silica FIGURE 4. -Generalized cross section, northwest to southeast, across Hollidaysburg and Huntingdon quadrangles, showing restored positions of to form the chert of the Mines. Mines conditions continued the eroded strata. through Larke time except that the deposits seemed to be almost Horizontal shortening 5 miles. without silica of any kind. Drab. There is probably no anticline or arch of greater mag­ GEOLOGIC HISTORY In the Nittany epoch calcareous sediment, later becoming dolomite, was deposited; during the succeeding Axemann epoch nitude in the Valley and Ridge province. PROTEROZOIC ERA The Broadtop trough is a great syncline or down bend in the limestone intermixed with dolomite layers was laid down; and In the Proterozoic era were deposited stratified rocks older strata. Its breadth, measured from the crest of the Nittany in the Bellefonte epoch calcareous sediment that merges into than the earliest rocks that contain an abundance of recognizable arch northwest of Drab to the crest of Jacks Mountain, about 1 dolomite was again deposited. Throughout these three epochs fossils. At the end of the era these rocks formed a land mass mile east of the southeast corner of the Huntingdon quadrangle, of Beekmantown time gastropods were the predominating forms in the central United States and another one extending along is about 20 miles. In the bottom of the trough, in the south­ of animal life, with fewer cephalopods, brachiopods, and trilo­ the Atlantic coast from Newfoundland to Florida. Between the east corner of the Huntingdon quadrangle, the Warrior lime­ bites, and plant life in very low form was represented by Cryp- two land masses a comparatively narrow trough known as the stone, which crops out on the crest of the Nittany arch 1 mile tozoa, which are supposed to be lime-secreting algae. Appalachian Strait extended from the Gulf of St. Lawrence northwest of Drab, is about 5 miles below the summit of Rocky Beekmantown time was followed by an unrecorded interval through central Pennsylvania to the Gulf of Mexico. Proter­ Ridge. corresponding to the early part of the Chazy epoch, the rocks ozoic rocks formed the bottom of this strait and made the foun­ As the strata in these folds were originally horizontal they of which, several hundred feet thick, are believed to be absent dation upon which the overlying Paleozoic rocks in this now occupy a less width in the earth's crust than they did in this region. The absent formations are the St. Peter sand­ region were deposited. before the folding. The total crustal shortening between stone of the Mississippi Valley and most if not all of the Jacks Mountain and the Allegheny Front is 5 miles that is, PALEOZOIC ERA Murfreesboro limestone, 500 feet thick, of Tennessee. The points on the Tuscarora quartzite or any other bed would be The Paleozoic era is the era of ancient life. All the great whole Appalachian Valley probably was dry land of very low 5 miles farther apart than now if the strata were restored to classes of invertebrate animals were already differentiated at its relief during most of the unrecorded time. Later the sea, grad­ horizontality. beginning, and the lower classes of vertebrates, the fishes and ually transgressing from the southwest, again submerged central These great folds are not simple symmetrical features, but amphibia, appeared before its end. Pennsylvania in Middle Ordovician time, and in this sea the are somewhat steeper on their northwestern than on their south­ Carlim limestone was deposited. Transgression of the sea from CAMBRIAN PERIOD eastern limbs and. have subordinate folds or wrinkles on their the southwest is inferred from the fact that the Murfreesboro flanks or crests. The Broadtop trough has a wide, nearly flat In the early part of the Cambrian period coarse sediment was limestone is believed to be present in southwestern Virginia, bottom, and if the section shown in Figure 4 had been located discharged from the bordering lands into the Appalachian Strait where it was laid down in the transgressing water before the farther south, as on the line of section E-E' of the Hollidays- and formed strata of sandstone, conglomerate, and shale in submergence reached central Pennsylvania. The Lemont burg quadrangle, or had been located 10 miles northeast of the places supposed to be more than 10,000 feet thick. These rocks, argillaceous limestone, the top member of the Carlim, grows quadrangle, it would show a broad, nearly flat crest on the now cropping out in South Mountain, Pa., and along the Blue thicker toward the northeast, and possibly its materials came Nittany arch. Ridge of Virginia, are believed to extend westward in places at from that direction. Shallow water is indicated by ripple marks A notable feature of the structure is the Scotch Valley syn­ least and to underlie the Hollidaysburg and Huntingdon quad­ and mud cracks on some of the limestone layers. Bryozoa, cline. This fold may be regarded as a deep depression in the rangles at considerable depth. brachiopods, pelecypods, gastropods, ostracodes, and trilobites northwest lirnb of the Nittany arch, to which its narrowness in The deposition of limestone followed, and the Tomstown dolo­ were the principal inhabitants of the Carlim sea and were most the northern two-thirds of the quadrangles is due. mite of Pennsylvania, which is supposed to underlie the abundant in Lemont time. The minor anticlines and synclines, shown by their axes, Waynesboro formation in these quadrangles, and the equiva­ For a very long time after the Carlim epoch the central include the Sinking Valley, Roaring Springs, and Woodbury lent Shady dolomite of the southern Appalachian region were Pennsylvania region was dry land, or, at most, only slightly anticlines and the Scotch Valley, McCue, and Trough Creek laid down. The deposition of this limestone indicates a change submerged, whereas the sea covered other parts of the Appa­ synclines. of geographic or climatic conditions, possibly a wearing down lachian Valley province, as in eastern Tennessee, where 6,000 The crest of the Nittany arch is also broken by the Halter or sinking of the land, from which the slow-running streams to 8,000 feet of strata (Blount group of Ulrich), including the Creek, east and west Henrietta, and Williamsburg faults, along would carry little or no sediment to the strait, or possibly a Holston marble, Athens shale, Tellico sandstone, and Sevier which, except the east Henrietta fault, the strata have been desert condition with no drainage. Again the conditions shale, are believed to have been deposited between Chazy and thrust upward and westward into contact with younger rocks changed, and red and green mud, sand, and fine gravel were Black River time. This unrecorded interval was thus a very on the west, as shown in the structure sections. The strati- deposited, making the rocks of the Waynesboro formation. long one. graphic displacement on the Halter Creek fault at the south The red mud could have originated through the deep decay of In Lowville time the transgression of the Ordovician sea edge of the Hollidaysburg quadrangle is 5,000 feet, the Warrior the rocks of the land during Tomstown time, when there was reached its culmination, and the central part of the United States limestone being thrust up into .contact with the Reedsville shale. little erosion, red sediment being commonly regarded as a result at least was very largely submerged, for in the Eastern States The displacement on the west Henrietta fault, due east of of desert conditions. Quartz pebbles in these conglomerates rocks of Lowville age are probably the most widespread of all Martinsburg, is also about 5,000 feet. Elsewhere the displace­ may have come from the Piedmont region, a hundred miles in the Ordovician system-. Life was fairly abundant, especially ment is less. away. Scarcity of life in the region is indicated by the fewness in Rodrnan time, and bryozoans, brachiopods, gastropods, and The faults throughout most of their extent are strike faults, of the fossils in the Waynesboro rocks. The second change to corals were the most common forms. but in places they cut across the strike, notably the east and limestone deposition in the Pleasant Hill and Warrior epochs Although the deposition of limestone persisted in this region west Henrietta faults and the Williamsburg fault in the north­ may plausibly be associated with a period of widespread sub­ during Trenton time, it is known that terrigenous rather than west corner of the Huntingdon quadrangle. mergence of the area now the interior of the United States, calcareous sediment was being deposited in eastern Pennsyl­ The relations brought about by the Henrietta faults are during which shore lines were far removed from this region. vania, where the lower part of the Martinsburg shale is of Tren­ unusual. The rocks on the east of the west fault are upthrust, The Pleasant Hill sea was invaded by trilobites and brachiopods ton age. Some of the carbonaceous matter, to which the dark and those on the east of the east fault are relatively down- near the end of this epoch. Precipitation of calcium carbonate color of much of the Martinsburg shale is due, and perhaps a thrown. If the wedge of older strata between the faults from the water, possibly through the agency of bacteria or algae, little of the finest clay sediment were conveyed, to this region, were withdrawn and the resulting gap closed, the correspond­ continued through the Warrior epoch. Most of the Warrior giving the Trenton limestone its shale partings, impurities, and ing formations on opposite sides of the gap would nearly deposit, however, is now a dolomite or magnesian limestone, dark color. The same general forms of life inhabited the Tren­ match end to end. The present relations are such as would probably the product of a concentration of magnesium salts in ton sea as were in the seas of the preceding epoch, although of be brought about by the formation and opening of a fracture the sea water caused by rapid evaporation. different species. due to tensional strain in the arching of the strata, the branch­ Some of the geographic conditions at this time are indicated The deposition of the succeeding Reedsville shale marked the ing of the fracture at depth, and the pushing upward of the by the sandy layers of the Warrior. The Hollidaysburg-Hunt- beginning of a great change in geographic conditions in the wedge between the branches by the enormous compressive ingdon region must have been near the shore of the Warrior Appalachian Gulf. Uplift of the sea floor, warping, shallowing forces involved in the folding acting upon the broad base of the sea, where streams carrying the sand and coarser quartz of the water, and finally a dominance of clastic sediments more wedge. The present conditions may have been brought about grains debouched. pronounced than had occurred in the region since early Cam­ in some such way. Trilobites and oboloid brachiopods lived in the sea from brian time are the distinguishing features of the Martinsburg, The rocks of the region are but slightly affected by minor time to time, as shown by their fossil remains found at several Reedsville, and succeeding epochs up to the Tonoloway. Not structural features. Slaty cleavage has been produced in the horizons. Cryplozoon undulatum, a species of marine alga, a only in central Pennsylvania but also over a very large region Reedsville shale in places where it has been squeezed most as in low plant form, was one of the principal inhabitants of the in the eastern United States the deposition of fine mud was the the angle between Short and Loop Mountains. Some of the Tus- Warrior sea. (See pis. 7, 8, and 0.) rule during the Reedsville epoch. The strait had probably Hcllitlaysburg-Huntingdon become a broad, comparatively shallow gulf agitated by great region of the Catskill Mountains in southeastern New York of a very old land surface such as exists today in parts of the waves and swept by tidal and possibly strong oceanic currents. and extended southwestward into southwestern Virginia and Southern States. This land may have been in the Adirondacks Conditions were generally favorable to life in this epoch, and over most of West Virginia and eastern Ohio. The Holli- or New England region. The gray shale and sandstone strata at different times the sea bottom must have been covered with daysburg-Huntingdon area was continuously submerged and occurring at several horizons in the Hampshire and bearing a shell-bearing animals, for many thin layers of impure limestone received deposits of clay and sand during the whole of the marine fauna as described above may have had a northwestern composed of these shells are intercalated in the shale. period following the Helderberg epoch. source or may have been derived from the same source as the red In the epoch succeeding the Keedsville there were probably The narrow Helderberg sea of the central Appalachian region sediment and been bleached by the decaying organic matter of lands of moderate relief on the northwest in Canada and on the extended from New York through central Pennsylvania to the marine water. southeast in the Blue Ridge province, but fora time at least southwestern Virginia and was probably surrounded by very In the latter half of Devonian time two notable events in the they underwent relative elevation; the shores moved seaward low lands on which slight erosion was going on. Deposition history of the earth came to pass land plants and primitive and exposed to subaerial erosion the old submerged coastal shelf, of limestone prevailed, and conditions were favorable to life. fish became fairly common, remains of which are present in the where lay a large body of sandy residue left after the finer mate­ Many of the inhabitants of the Helderberg sea were survivors Hampshire of Pennsylvania. rial of the Martinsburg shale was washed out and laid down from the Silurian, and some new types were introduced. farther seaward. This sandy shelf, now become a coastal plain, The Oriskany epoch marked the beginning of a revival of CAKBONIFEKOTJS PERIOD and the higher land farther from the shore supplied the sandy the transporting power of streams. Fine sand was mixed with material of the later formations of the Ordovician. calcareous sediment to form the thinner siliceous limestone of In the Hollidaysburg-Huntingdon region sedimentation Thus the deposits of the succeeding Oswego epoch were pre­ the Shriver, and later with growing transporting power still apparently went on continuously from the Devonian period dominantly fine quartz sand. The absence of the Oswego south­ coarser sand and small quartz pebbles were delivered by the into the Carboniferous. As the oldest Pocono seems to be of east of this region, nearer the Appalachian Mountains, and its streams to the highly calcareous seas to form the calcareous Burlington and Fern Glen age, this would imply that the Kin- presence in central New York indicate an old land northwest Bldgeley sandstone. The Appalachian Gulf in the Oriskany derhook is represented in the upper part of the Hampshire. of the Appalachian Strait as the source of the sandy sediment. epoch extended from Canada to southwestern Virginia, and per­ The distinguishing feature of the Carboniferous period, especi­ During the succeeding Juniata epoch the deposition of sandy haps the Appalachian Valley area was occupied by shallow ally its later half, was the abundant vegetal growth, which and muddy sediments continued. Considerable variation in lagoons as far south as Alabama and Georgia, where isolated supplied the material for coal. It was a time of warm climate the kinds of sediment discharged into the water or in the trans­ Oriskany deposits occur. During Shriver time conditions were and extensive marshes near sea level, in which plants of differ­ porting power of the currents by which the sediment was dis­ less favorable to life than in Helderberg, but in Bidgeley time ent kinds grew luxuriantly and on falling were covered by water tributed is attested by the alternating beds of shale and sand­ they again became favorable, and the sea bottom was thickly and so preserved from decay in the same manner as vegetal stone. It is supposed that the red sediments predominating in populated by shell-bearing invertebrates, especially brachiopods debris is preserved in the peatbogs of the present day. the Juniata were derived from an area on the east upon which and gastropods. In this region the same oscillations between marine and non- had accumulated a deep residual soil. This iron-stained soil In central Pennsylvania during Onondaga time fine argil­ marine conditions as in the Hampshire persisted in at least the was transported toward the western sea of the time, occupying laceous and calcareous sedimentation prevailed. On the north first half of Pocono time. Nonmarine conditions were fully a large area in Ohio, Indiana, Kentucky, and Canada, and was and west in New York and Ohio only limestone was laid down. established in the later part of the epoch, when the Burgoon deposited as a great delta similar to that now forming along The shale and limestone of this area were near-shore deposits, sandstone member was laid down. the lower course of the Yellow Biver in China. and the limestone on the north and northwest was deposited As the Loyalhanna limestone probably represents the Ste. farther from shore in clear water. Animal life was not abun­ Genevieve limestone, no representatives of Keokuk, Warsaw, SILUHIAN PERIOD dant in the Hollidaysburg-Huntingdon region, but in some Spergen, and St. Louis formations are present in this region, so The Tuscarora epoch was one of widespread deposition of pure parts of the Onondaga sea it was profuse. there is an unrecorded interval of considerable length between quartz sand in the Appalachian region. The formation implies The rocks of the Marcellus, Hamilton, Genesee, Portage, and the Burgoon and Loyalhanna epochs. The Loyalhanna. lime­ much erosion of tributary land and much sorting of material, Chemung formations were laid down in a more or less land­ stone shows considerable resemblance to wind-blown deposits which left a mantle of comparatively coarse sand on the low land locked bay or gulf, the head of which was in southeastern New of oolite in the Bahama Islands and probably had a similar of a wide coastal plain. York. The clay, silt, and sand of which they are composed origin. The carbonate of lime may have been carried by wind The absence of fossils in the Oswego, Juniata, and Tuscarora were apparently derived from land on the northeast and south­ from its source on the southwest into the probably very shallow formations is regarded as very strong evidence that they were east, whose western shore probably extended from New York waters of the Appalachian Gulf and widely distributed over all terrestrial, perhaps shore deposits, exposed to the air all or southward some distance west of the present line of the Blue the lowlands bordering the Mississippian sea on the east and part of the time and laid down before air-breathing animals had Ridge. The character of these formations indicates accumula­ mixed with quartz beach sand at the same time. The absence appeared upon the earth. Similar deposits of later times con­ tion in shallow water, which involves a long period of slow and of fossils and the extreme cross-bedding indicate a partly tain the tracks and fossil remains of air-breathing animals. constant subsidence of the floor of the Appalachian Gulf in terrestrial wind-blown origin. During the Clinton epoch the region was again submerged in order that 7,000 or 8,000 feet of shallow-water deposits might The deposition of the prevailingly gray Pocono was succeeded the sea, which at times swarmed with ostracodes and other accumulate therein. by a third extensive deposition of redbeds, composing the invertebrates. The feature, however, that peculiarly distin­ The Marcellus sea was sparsely populated except by small Mauch Chunk formation. The conditions in Pennsylvania guishes the Clinton formation is the occurrence of beds of fossil pteropods (Slyliolina), which were abundant. So was the during Mauch Chunk time were unfavorable for invertebrate and oolitic iron, ore. These beds are present along the Appa­ Hamilton sea in central Pennsylvania, except near the end of and plant life, for the formation contains no coal beds and lachian Valley from New York to Alabama and point to a its existence, when bryozoans and brachiopods flourished and shows little evidence of the presence of either plants or animals. remarkable uniformit}^ of conditions. That the iron was many other forms were common. The inhabitants of the At the same time, however, in western Pennsylvania and deposited contemporaneously in the beds in which it occurs is Portage sea were peculiar diminutive pelecypods and gastro­ eastern Ohio, marine limestones and shales were being deposited the most generally accepted theory. Extensive more or less pods that seem :to have lived in small numbers throughout the upon a sea bottom thickly inhabited by marine invertebrates, sheltered lagoons in which animals flourished may be conceived. time and some larger and still less abundant cephalopods. whose fossil remains now crowd the Greenbrier limestone The shells and other skeletal parts of the animals, usually in The Chemung fauna was more abundant and the forms of life member of the Mauch Chunk of Pennsylvania and the a comminuted state, such as the coquina found in Florida at were larger, brachiopods and pelecypods predominating in contemporaneous Maxville limestone of Ohio. the present time, accumulated in these lagoons, and as calcium number of species and individuals. After the deposition of the Mauch Chunk an unrecorded carbonate precipitates iron from solution the iron, possibly Before the beginning of Chemung deposition in fact, soon interval ensued in this region that was long enough for the brought into the lagoons in solution as iron carbonate or iron after Hamilton time the redbed facies of sedimentation began deposition of 10,000 feet of rock, including many coal beds in sulphate, was precipitated and mixed with the animal debris, in southeastern New York with the deposition of the Oneonta the Pottsville troughs of Alabama. If these beds were present the calcium carbonate of which it finally replaced to form the ore. sandstone. From this time onward the deposition of red rocks in this part of Pennsylvania, they would lie between the top of Between the Clinton and McKenzie epochs is an unrecorded continued, being contemporaneous at first with the marine Port­ the Mauch Chunk and the bottom of the Pottsville bed as interval during which the Lock port dolomite, absent in Penn­ age, later with the Chemung, and at the end probably with early described below. sylvania, was deposited in New York and Canada. Mississippian deposits. Thus it happens that the redbed facies At the beginning of Pottsville deposition there was a sinking Pure limestone marks the beginning of the McKenzie epoch. diminishes in thickness from the bottom upward as it extends trough in eastern Pennsylvania extending southward, bordered Later argillaceous sediments predominated. Animal life flour­ westward, until it is represented in western Pennsylvania and by land, probably high around the north end and on the south­ ished and ostracodes and brachiopods were very abundant. New York by only a few hundred feet of rocks characterized by east, and by lowland on the northwest. From these lands the Following McKenzie time the few beds of the red sandstone beds of red shale. As a whole, however, the redbed facies is rapid streams brought in immense quantities of coarse material. and shale of the Bloornsburg redbeds were deposited. best explained as a dry delta deposit extending from the Cats- This deposition of coarse material went on until 1,000 feet of In Wills Creek time fine sediment, at rare intervals calcareous, kill Mountains to Maryland and West Virginia, the upper one- strata, containing coal beds, was laid down in the southern seems to have been laid down everywhere. In marked contrast third or so of which is represented in western New York and anthracite field of Pennsylvania and 10,000 feet, containing with the McKenzie sea the Wills Creek sea in this region was northwestern Pennsylvania by prevailingly marine fossiliferous many coal beds, in Alabama. While these masses of Pottsville very nearly destitute of inhabitants. The salt and gypsum sediment in which are local red layers. In the Hollidaysburg sediments were accumulating the land from central Pennsylvania deposits of the equivalent Salina formation of New York indi­ and Huntingdon quadrangles the delta type of sediment pre­ westward had been worn down nearly to sea level and then cate a more or less isolated body of water and an arid climate dominates, but at times the western margin of the delta was in the later part of Pottsville time it was submerged and sedi­ with excess of evaporation. Such conditions, though perhaps submerged from the west and tongues of marine fossiliferous mentation upon it was resumed. This sedimentation produced less extreme, may have existed in central Pennsylvania during sediment were laid down. first the Connoquenessing sandstone the lowest member of the the epoch. w. Pottsville of these quadrangles. During the Tonoloway epoch the deposition of nearly pure Catskill Mts. Deposition continued from the Pottsville into the Allegheny calcareous sediment, for the first time since the Trenton epoch, epoch, which was marked by rapidly alternating conditions, and Allegheny was resumed in this region. Land was probably far distant. Front as a result shale, sandstone, limestone, and coal beds succeeded one another at short intervals. Practically all the coal in west­ DEVONIAN PERIOD ern Pennsylvania occurs in the Allegheny or in higher forma­ By the beginning of the Devonian period the Appalachian tions that do not now exist in these quadrangles. Deposition FIGURE 5. Sketch section from the Catskill Mountains of New York to continued in the region at least through Conemaugh and Gulf had contracted to a rather small basin occupied by the sea the Allegheny Front in Pennsylvania, showing the relations of the of earlier Helderberg time, supposedly connected with Atlantic Hampshire and Catskill formations. The shading indicates red shale Monongahela time, as indicated by the presence of rocks of waters. This sea expanded to the southwest and possibly to and red sandstone which diminish westward and rise into higher those epochs in Broadtop Mountain, south of these quadrangles. formations. the northeast and after Onondaga time received a vast amount No history of these quadrangles during Permian time, the of sediment from the highlands on the east and northeast, which It is thought that the red sediment was derived from the final epoch of the Paleozoic era, has been preserved, but a spread out delta-like from the head of the sea or gulf in the highly oxidized residuum of deeply decayed crystalline rocks considerable thickness of Permian rocks (Dunkard group) was deposited in the extreme southwest corner of the State, and rose eroded their beds to lower levels while the side streams Axemann limestone.- The Axemann limestone has been quar­ probably Permian rocks were deposited in this region also. wore down their valleys on the more easily credible rocks ried on a small scale by farmers and burned for agricultural between the harder strata of the ridges. Thus the streams lime. MESOZOIC AND CENOZOIC ERAS have sawed, so to speak, the gorges through the ridges. Point Carlim and Lowville limestones. All the large quarries of The Paleozoic era had been one of sedimentation in the View knob (pi. 2) was separated from the north end of Lock the region are opened on the Carlim and Lowville limestones, Appalachian Valley and Appalachian Plateaus, during which a Mountain in this way. and the combined thickness of about 360 feet is generally great series of rock formations was built up. The Mesozoic and quarried. The argillaceous and siliceous Lemont member in GLACIAL EPOCH Cenozoic, on the contrary, were eras of deformation and erosion. the top of the Carlim, unless quarried for ballast or road metal, Very few and fragmentary records of the events of these eras In the Pleistocene epoch of the Quaternary period the north­ is rejected. have been preserved in the Appalachian region, although evi­ ern and central parts of the United States were covered a num­ The composition of these limestones differs from bed to bed, dence that vast changes occurred is plainly to be seen. To a cer­ ber of times by great ice sheets from the Canadian highlands, but the average content of insoluble matter for the entire thick­ tain extent the history of the region can be inferred from records but these did not reach the Hollidaysburg-Huntingdon region, ness, excluding the Lemont member, is somewhat less than 5 th^t persist in other parts of the country. the southern margin of the ice advance in Pennsylvania being percent. The following statement was given by the superin­ 100 miles or so to the north. APPALACHIAN UPLIFT tendent at the quarry: KECENT EPOCH The Dunkard epoch brought sedimentation in the north end Average composition of limestones in Blair No. 5 quarry, about S miles of the Appalachian trough to a close, and a long series of events In the Recent epoch of the Quaternary period the final sculp­ north of Carlim turing of the region to its present topographic aspect was effected, Calcium carbonate (CaCO s)______._____._ 90.739 of a totally different kind began. So far as known, from the Alumina (A12 O3)______.______..___..___ 1.000 close of Carboniferous deposition until the present time dry land and the Recent deposits of alluvium were laid down along the Silica (SiO s)____._____.______..______3.75 lowlands bordering the streams. Magnesium carbonate (MgCOs)______4.50 has existed in the north end of the Appalachian Valley, except Sulphur (S).______.009 in the areas occupied by the Triassic basins that existed from PKOGKESS OF LIFE Phosphorus (P)______.__..______. ___ .004 place to place from Connecticut to North Carolina. Uplift of It is probable that the terrestrial plants and animals of Mes­ 100.002 the sea bottom was accompanied by strong deformation, by ozoic and Cenozoic time, whose existence is recorded by their which the originally horizontal sedimentary strata of the Appa­ The following analyses 3 ° show the composition of the lime­ remains in the rocks of those eras along the Atlantic and Gulf lachian Valley were folded into high anticlines and deep syn- stone in a quarry at Franklin Forge (Ganister): coasts and in the Rocky Mountains, flourished in this region clines, and west of the Allegheny Front into the low anticlines also. The cycads and ferns of the Triassic and Jurassic periods Analyses of Carlim and Lowoille limestones at the quarry of St. Glair and shallow synclines of the bituminous coal fields. This fold­ Limestone Co., at Franklin Forge doubtless clothed the surface of the land and supplied nutriment ing must have taken place in Mesozoic time because the youngest to the great reptiles (dinosaurs) and the small mammals that, Paleozoic strata (Dunkard group) are involved in it. This from tracks and skeletal remains found in Connecticut and profound change in the history of the region is known as the Calcium carbonate (CaCO s) ______91.07 94.00 North Carolina, are known to have been living in the region as Appalachian revolution. Magnesium carbonate (MgCO3) ______5.04 3.00 early as Triassic time. Probably the kinds of fish characteristic Iron and alumina (Fe2 O8 , ALO3)_ ___ _ 1.10 CYCLES OF EKOSION of the times swam in the rivers and creeks of the region. But Silica (SiO8) 4.20 2.00 The wearing away of land by processes of erosion is ceaseless. no vestige of this life remains, because all deposits in which any Undetermined ______1.00 If a region should cease to rise or the upward movement become of the plants or animals could have been buried and preserved 101. 41 100. 00 very slow, the land would in time be worn down to a plain near were later swept away in the general erosion of the region. to sea level. A surface thus reduced is called a peneplain. In the Cretaceous period great forests of deciduous trees must Samples that were taken from a quarry near Martinsburg, Should a second uplift occur, erosion would be renewed and as have grown in which must have roamed other forms of gigantic probably in the Carlim limestone, had the composition shown before would proceed faster on soft rocks, forming valleys, than dinosaurs than those of Triassic or Jurassic time. In this below: period such common kinds of trees as the oak, willow, sassafras, on harder rocks, which would be left standing as ridges between Composition of Carlim limestone from quarry near Martinsburg valleys. The tops of these ridges would for a long time ap­ and tulip tree (yellow poplar) first appeared upon the earth. proximately coincide with the surface, now uplifted, of the old All traces of these Cretaceous plants too, have been obliterated i 2 peneplain. Such cycles of erosion may be several times re­ in this region, although their remains, especially leaves, are abundant in the Cretaceous deposits in New Jersey, Maryland, Calcium carbonate (CaCO8) ______91.08 98.00 peated and leave remnants of the successive peneplaned surfaces Magnesium carbonate (MgCO 3)__ __ _..__ 3.99 at accordant levels as a series of hill or ridge tops, or benches and Virginia, having been borne into the bordering Cretaceous Iron and alumina (Fe3 O a , AUOg). ______.86 along the valley walls, or spurs extending out from them. seas by streams and winds. In Tertiary time many strange Silica (SiOo) ______... __ 3.07 With these broad principles of erosion in cycles as a clue some forms of mammals, known from their remains in the Rocky Other minerals ___ 1.05 inferences as to post-Paleozoic history of this region can be Mountains, probably inhabited this region also, and in Pleisto­ Undetermined 2.00 drawn from the land forms now existing. cene time extinct animals whose remains are now found in the 100. 05 100.00 Kittatinny peneplain. It is believed that during Triassic and swamps, bogs, and caves of the region were the common deni­ 1. Quarry of Isaac Campbell, Martinsburg. Jurassic times the surface of the uplifted and folded Appalach­ zens of the land. In a cave at Smith's quarry, half a mile west 2. Credited to John Manning, quarry in vicinity of Martinsburg. ian Valley was eroded, possibly more than once, to a peneplain. of Frankstown, Pa., were found remains of a tapir, a ground The first of these, if there was more than one in these periods, sloth (Megalonyx), two species of peccary, a bison, a mastodon, Tonoloway limestone. The top of the Tonoloway limestone is called the Kittatinny peneplain, because remnants of it are and a carnivore resembling the jaguar. 27 In a cave near east of Tussey Mountain is, locally at least, of good quality, as well preserved on the flat tops of Kittatinny Mountain in eastern Cumberland, Md., there have been found, among many shown by analyses 3, 4, and 5 below of samples from the old Pennsylvania. The crests of Dunning and Tussey Mountains species, a horse and an eland, 28 the latter now known only Powell quarries. and other hard sandstone ridges in Blair County and the crest in Africa. Helderberg limestone. The Helderberg has been largely of the Allegheny Front also approximately represent the ECONOMIC GEOLOGY 29 quarried near Hollidaysburg, on the low curved ridge extending from Altoona past Duncansville and Newry to the vicinity of uplifted surface of this peneplain. STONE Sehooley peneplain. After the uplift of the Kittatinny pene­ Canoe Creek, 6 miles northeast of Hollidaysburg. Its compo­ plain erosion produced a second peneplain, parts of which may LIMESTONE sition ranges from 90 to 98 percent of calcium carbonate, 0 to be the summits at 1,500 to 1,800 feet above sea level on the Limestone is a valuable resource of this region. Large quan­ 5 percent of magnesium carbonate, about 5 percent of iron eastern foothills of the Allegheny Front and possibly the con­ tities have been used for flux in the blast furnaces of Pittsburgh. oxide, alumina, and silica, and a negligible quantity of sulphur spicuous bench about 1,800 feet above sea level on the outcrop Some is burned for lime, some used in the glass industry, and and phosphorus. of the Oswego sandstone along the east side of Tussey Mountain some for fertilizer. Five formations yield commercial rock the If lime suitable for paper making or ground limestone for and the west side of Lock and Dunning Mountains. This Axemann limestone, Bellefonte dolomite, Carlim limestone? glass making is desired, only the "calico rock" at the base of peneplain is correlated by some with the Sehooley peneplain, Lowville limestone, and Helderberg limestone (Keyser member). the Keyser member is used. The "calico rock" and most of developed on Sehooley Mountain in northern New Jersey. Bellefonte dolomite. The Bellefonte dolomite, quarried at the rock for 50 feet below it (Tonoloway) has been quarried for It is believed that the Sehooley peneplain was completed bv" the the Clover Creek quarry, southeast of Williamsburg, is used for flux a mile west of Canoe Creek. In the vicinity of Altoona beginning of Upper Cretaceous time, for in New Jersey a rem­ flux. About 50 feet at the top has been utilized. Its high per­ the crystalline limestone above the "calico rock" is quarried for nant of what is supposed to be that peneplain extends seaward centage of magnesia unfits the rock for making cement. Some concrete and road metal, and at the Frankstown quarries it is beneath deposits of Upper Cretaceous age. The Kittatinny of the rock from the vicinity of Wertz has been used for back burned for fertilizer lime. peneplain then was completed in an earlier period, perhaps the walls of furnaces. The composition of the rock is indicated by The composition of the "calico rock" and adjacent beds is Jurassic. the following analyses: shown in the following tables, which were furnished by J. K. McLannahan: Harrisburg peneplain. After the formation of the Sehooley Analyses of dolomite from Hollidaysburg-Huntingdon region peneplain the region was again uplifted, erosion was renewed, [Analyses by Cambria Steel Co.] Composition of samples taken from 34 feet of limestone, including the and the broad, rolling area of Morrison Cove, now 1,200 to "calico rook" at old Reservoir quarry, about 1 mile southwest of i 2 8 4 5 6 7 8 Hollidayslturg 1,400 feet above sea level, was developed. This area possibly represents the Harrisburg peneplain, well developed near, CaCO3 -_ 54.43 53. 38 50.58 50.93 48.39 48.29 44-52 54-95.75 1 2 3 4 5 6 Harrisburg, where its altitude is about 500 feet. MgC0 3 __ 38.20 41.84 41.08 41.52 40.86 41.43 35-42 . 90-39. Post-Harrisburg erosion. The Harrisburg peneplain is sup­ A1S 03 1 .68 .72 .92 .88 1.06 . 49-3. 37 . 40-2. 25 CaCO8 .__ :_-______86. 78 96.72 95.09 95.01 92.84 95.22 SiO s - __ _ 8.44 1.90 1.55 1.18 1.26 1.86 posed to have been uplifted unequally, and modern stream val­ Si(V____ 4.76 2.40 5.78 4.94 8.04 7.22 3. 34-12. 34 1. 26-6. 57 Fe3 03 ___ .70 .70 .84 .70 .84 .98 MgC0 3 ______.31 1.96 1.10 1.96 1.79 1.40 leys have been eroded below its surface in the later part of s .04 A18 0,______.81 .80 1.40 .53 2.91 72 Tertiary time and to their present depths in Quaternary time. P______. 03-. 11 . 008-. 015 Fe,Os -_-._ .09 .12 .18 1.10 .15 .11 .Development of drainage features. When something is 99.09 99.00 99.00 99.00 99.01 98.98 known of the history of the region since the Appalachian revo­ Mr. McLannahan states that the "calico rock" at the Reser­ lution as outlined above, it is easy to understand the origin of "Average SiO3 from 31 analyses, 3.72. voir quarry became so siliceous along the strike that the quarry 1-6. Bottenfleld farm, 2 miles southeast of Williamsburg. such gaps through the ridges as McKee Gap, and the gap of 7. Dolomite near Carlim. Extremes of a number of analyses. had to be abandoned. Frankstown Branch of the Juniata at Point View. The streams 8. Dolomite from Fox Hollow, 1 mile north of Carlim. Extremes of 31 that occupy these gaps took their courses 011 the nearly level analyses. 30 Pennsylvania State Coll. Agr. Exper. Sta. Bull. 127, p. 79, 1913. surface of the Kittatinny peneplain, which was topographically "Holland, W. J., Carnegie Mus. Annals, vol. 4, pp. 223-228, 1906-8. 28 Gridley, J. W., II. S. Nat, Mus. Proc., vol. 46, pp. 93-102,1913. above the tops of the ridges of the present day. During subse­ 3 "This chapter was written about 1915. Present conditions differ in quent uplifts they maintained their courses and as the country same particulars. Hollidaysfourg'-Mantiiigdott 18

Composition of " calico rock" and beds above and below it at Analyses of ganister from Lock Mountain No. 1 is only a ferruginous sandstone here. The Frankstown quarries near Hollidaysburg and Frankstown [Isaac Reese & Sons Co., analyst] ore is highly fossiliferous and slightly oolitic, the oolitic grains

i g 3 4 5 i 2 3 4 5 6 7 being flattened and generally of considerable size. It much resembles the Alabama Clinton ore. Its composition is shown CaCO, ______88.34 89. 10 92. 07 98. 70 96.06 SiO8 _ 97.90 97.98 97.30 98. 65 99.10 98.15 98.20 in the following table: SiO, ______9.28 3.16 3.40 2.60 2.06 Fe2O,+Al 2 O 8 _- _ .90 .95 1.20 .30 .60 1.20 1.35 MgCO, 1.96 6.01 3.05 1.90 3.06 CaO _ .40 .25 .30 .25 None Composition of the Frankstown ore Al8 year's shipment. Analysis by 0.3 millimeter in diameter, but additions of silica that are crys- Sulphur______Trace Mr. Johnson, of the Harmsworth Steel Co. tallographically continuous with the original grains now fill the Water______.19 Metallic iron. East of Tussey Mountain the lower 20 feet of the Helderberg interstices and cement the original sandstone to a compact 47.15 and the upper 14|- feet of the Tonoloway limestone are of good quartzite. The high lime content indicates hard, unweathered ore, and quality as shown in the following table. The relations of these Economic qualities. There seems to be a difference of opin­ the metallic content shows a high grade for such an unweath­ beds are shown in section 5 of the chart on page 8. ion as to the qualities of ganister that make it suitable for silica ered Clinton ore. brick, although ordinary sandstone of the same composition is The part of the outcrop of the Frankstown bed that has been Composition of the lower beds of the Helderberg and upper beds of not suitable. Some think that brick from sandstone is less the Tonoloway limestone at the old Powell quarries at &rafton a worked is at the south end of Brush Mountain. From this area [Analyses by A. S. McCreath] refractory than that from quartzite; others think that brick in both directions the bed thins and becomes worthless. Along from sandstone will not stand handling before burning. Quartz Brush Run north of Hollidaysburg the slopes are reported to i 2 3 4 5 from a loosely cemented sandstone should not fuse at a lower have extended 400 feet west of the outcrop to a limit where the CaCO, _.- .. -- -.. 95. 536 98. 035 94. 642 95. 446 93. 035 temperature than that from a compactly cemented quartzite ore became too thin for profitable mining. The Frankstown MgCO. ______1. 589 .908 2.8 1. 135 1.816 like the ganister rock, so it appears probable that the suit­ mine produced a greater quantity of ore than any other, the Fe.O,+Al8 O« ____- .490 .410 .370 .520 .730 ability of the quartzite for brick is due to the superior strength output having reached 20,000 tons a year in the seventies. SiCK,, etc __..___ -. .._____ 1. 851 .420 .1.730 2.350 3.480 that it gives. This difference in strength is due to the fact that Platt reports the slope as 710 feet long and 218 feet deep in P .011 .011 .006 .006 .006 the constituent grains of ganister,- being firmly cemented 1879 or 1880. Since then it has not been worked. 99. 476 99. 779 99. 548 99. 475 99. 067 together, do not separate in crushing, but the whole mass Markksburg ore. The Marklesburg ore bed, just under the breaks up into angular fragments and slivers that can be Keefer sandstone, has been extensively mined in a narrow area a Pennsylvania Second Gfeol. Survey Rept. T, p. 125, 1881. 1. From top of crinoidal layer. pressed together into a cohering mass in molding and so make beginning about 1 mile north of Marklesburg and extending 2. From bottom of crinoidal layer. a brick that will not break easily in handling, whereas loosely northeastward to a point west of McConnellstown. The bed is 3. 4, and 5. From 14| feet of limestone just below "calico rock" and cemented sandstone pulverizes more or less completely into its regarded as Tonoloway. a typical fossil ore 1 foot to 1^ feet thick. The following sec­ constituent rounded grains, which do not interlock in molding tion was furnished by the operator of a small mine 1 mile north The limestone from the crinoidal bed is said to be preferred and so have but little coherence. of Marklesburg: by blast-furnace operators to that of any of the other beds of the Ganister should contain but very small quantities of lime or Helderberg and Tonoloway rock along Warriors Ridge. The iron, as their presence in larger quantities destroys the refractory Section of the Marklesburg ore near Marklesburg " calico rock," however, makes the whitest lime. Ft. quality of the brick. About 1.25 percent of iron oxide is said Sandstone, cap rock (Keefer sandstone member)______9 Conditions that affect quarrying. The quarry beds dip at to be the maximum percentage allowable. Ore______..______.______... 6-8 angles ranging from 10° to vertical, but most of them dip more Ocher; mining bench______4 BUILDING STONE Shale______than 25°. Very favorable conditions exist for quarrying the Shale and soft ore in alternating layers, 3 inches thick, Carlim and Lowville limestones along Clover Creek and Franks- Sandstones from the Juniata and Tuscarora formations and in some mines a layer of soft ore that may be 10 town Branch east and northeast of Williamsburg and along sandy limestone from the Shriver have been used for coarse inches thick.______3 Shale (No. 10 of section, p. 6) ______600: Piney Creek south of Ganister. Here the quarry bottoms are masonry, and the red and brown sandstone of the Hampshire located just above high-water level along the streams, and oper­ would probably be a good rock for this purpose. There does The ore probably carries a small content of calcium carbonate ations proceed horizontally. Some quarries begin on the end not appear to be any rock in the region suitable for superstruc­ in the unweathered condition, limy (hard) ore having been of the beds and proceed along the strike, as the quarry of the ture or ornamental work. encountered in places. Most of the ore mined, however, is St. Clair Limestone Co. at Franklin Forge (Ganister), or oper­ leached, soft, of spongy texture and spangled throughout with ROAD METAL ations may begin at the top of the beds and proceed against the small particles said to be specular hematite. The limestone, dolomite, and chert of the region furnish dip to the bottom of the Carlim limestone, as in the St. Clair LIMONITE OB, BROWN HEMATITE ORE quarry, or deeper, if the Bellefonte dolomite is quarried, as on abundant road metal, and the Tuscarora quartzite has been used the west side of Clover Creek. (See pi. 25.) Quarrying may for paving blocks on some of the Altoona streets and appears to A full and satisfactory account of the deposits of limonite or begin below the top of the quarry beds and proceed with the be durable. brown hematite was given by Platt. 3 2 The principal old work­ dip to a point where the Hodman limestone comes in at the IRON ORE ings were the Springfield mines, at Oreminea; the Bloomfield top of the quarry face and makes further operations in that mines, at Ore Hill; the Henrietta mine, at Henrietta; the Mil- direction impracticable. This plan has been followed in the The iron ores of the region are now of historical rather than lerstown red-ore bank; and the Rebecca mines, near Rebecca quarries on the west side of Piney Creek, where the beds dip practical interest. Iron mining and smelting has been practi­ Furnace. 40° W. under Lock Mountain. (See pi. 26.) cally abandoned since 1880, and most of the furnaces had gone Springfield mines. The main pits at Oreminea are on the When the rock available along the valleys has been quarried out of blast before that date. The iron ores are of two kinds Gatesburg formation. The ore occurred partly as lumps in a out, it will be necessary to open new quarries on the upland hematite or fossil ore, also called Clinton ore because it occurs residual mass of clay, sand, and sandstone fragments more than level, as near Martinsburg and around the south end of Lock in the Clinton formation, and limonite. 200 feet deep, inclosed by rock walls on the north, east, and and Loop Mountains, or to mine the rock down the dip below CLINTON OE, FOSSIL ORE west. On the bottom was a layer 6 feet thick of ore in lumps drainage level. The location and altitude of the outcrops of the and blocks embedded in clay. Most of this material was passed Ore occurs at four distinct horizons in the Clinton of this Carlim and Lowville quarry beds in their undeveloped area are through the washer. Some of the ore was of excellent grade. region the "block" or Levant ore, near the bottom; the shown on the areal-geology map. The following analyses show its composition: Frankstown bed, about 250 feet above the bottom; lean ore The outcrop of the Helderberg quarry rock is in general bands associated with limestone and shale through a thickness Composition of limonite from the old Springfield mines a coincident with the crest of the ridge along the middle of the [Analyses by A. S. McCreath] of 15 to 20 feet, 200 feet or so above the Frankstown bed; and strip of Helderberg around the point of Brush Mountain, along the Marklesburg bed, just beneath the Keefer sandstone member. the south side of Scotch Valley, and along Warriors Ridge east i 2 3 4 "Block" or Levant ore. The "block" ore has been found of Tussey Mountain. only in a local pocket a mile or so northwest of Marklesburg, 0.004 0.024 Sesquioxide of iron ______52. 428 73. 714 84. 428 78. 143 GANISTER where from an oolitic bed nowhere more than 6 feet thick about 1.344 .610 .368 .103 20,000 tons was mined by the Cambria Iron Co. The Old Occurrence and composition. An active industry of Blair Oxide of cobalt. _ _ Trace Powell mine, about 1 mile west of Foxton, where 5 to 6 feet of County is the exploitation of the rock known as ganister, from Alumina ______2.042 , 1.979 2.617 2.146 soft rich fossil ore is reported, was probably on this bed. Lime ______Trace Trace .070 .030 which is made refractory brick for several kinds of furnace lin­ Frankstown ore. The Frankstown is the only extensive bed .129 .309 .227 .493 ings. The name ganister is derived from the German Ganster, in the Hollidaysburg region. It was formerly worked by the Sulphuric acid ... ______..______.075 .072 .237 .147 meaning a spark, and is applied because the rock, which is very Cambria Iron Co. at the Frankstown slope, 1-J- miles northwest .080 .137 .123 .137 hard, will give a spark when struck with iron. Water 9.375 10. 510 8.672 11. 886 of Frankstown. According to Platt 3 1 , who visited the mine The ganister occurs as beds in the Tuscarora quartzite. Pos­ Insoluble residue. ______34. 700 12. 260 3.460 6.845 before it closed, the Frankstown bed ranges from 8 to 22 inches sibly the whole of the formation, 400 to 600 feet thick, may 36. 700 51. 600 59. 100 54. 710 in thickness and averages 15 to 16 inches. Its stratigraphic have the qualities of ganister. This formation extends through .936 .425 .256 .072 relations are shown in the following section taken from Platt: the mountain region of central Pennsylvania and makes the Sulphur _ _ .030 .029 .096 .072 Phosphorus .035 .060 .054 .060 conspicuous ridges of which Tussey and Dunning Mountains are /Section of beds inclosing Frankstown ore bed near Frankstown Ft. . in. examples. Point View knob (pi. 2) shows well the mode of a Pennsylvania Second Geol. Survey Rept. T, p. 173,1881. occurrence. 8. Blue slate, fossiliferous, holding three small ore pins 40 1. Mine No. 1, wash ore. 3. Mine No. 2, bombshell ore. 7. Upper bastard ore, sandy, fossiliferous, "worthless; 2. Mine No. 2, wash ore. 4. Mine No. 3, wash ore. The ganister of Blair County and vicinity is a nearly pure blue slate, "bearing-in" slate____..______2 silica rock, as shown by the table giving the results of analyses 6. Frankstown ore bed, averaging.______.______1 3 The samples analyzed, except No. 3, were taken from the 5. Slate holding two small ore pins__-_____----__.._ 10 of samples from Lock Mountain near Point View. The data 4. Chocolate-colored slate______,____ 20 washer and represent the ore as it went to the furnace. were furnished by Mr. J. D. Hartman, of Hollidaysburg. 3. Slate?__....______-______.__._... ___^ 130 Bloomfield mines. The Bloomfield mines, on the ridge south 2. Slate and sandstone.______50 of Ore Hill, like the Springfield mines, are on the Gatesburg The specific gravity of ganister ranges from 2.46 to 2.58. 1. Keel iron ore, or hard fossil ore (Levant or "block" The Pennsylvania ganister is a compact light-gray to white ore) _____.. __.___ __-______._...._ 10± formation. The ore is in all respects similar to that at Spring- quartzite with somewhat vitreous luster. It becomes more or 31 Platt, Franklin, op. cit., pp. 137-152. 33 Platt, Franklin, op. cit., pp. 153-246. 19 field. The ore-bearing residuum extends over a space 7,200 feet Coals from these beds farther south in the Broadtop field are Bellefonte dolomites much chert in large boulders and smaller long and 1,000 to 1,500 feet wide, and the known depth is more shown by analyses to be of semibituminous grade. Appar­ fragments is scattered over and mixed through the soil. than 200 feet. The deposit is clearly in a deep rock depression ently the small area of the Allegheny formation in the north­ Although derived from limestone and dolomite this soil is bordered on the north, west, and south and perhaps on the east- west corner of the Hollidaysburg quadrangle includes very little deficient in lime, which has been removed by solution. It holds also by rock walls. The Bloorafield ores average, according to if any coal. water,well and except the Holston is.the most productive soil analyses published by Platt, 33 from 32 to 55 percent metallic CLAY AND SHALE of the quadrangles; corn, wheat, grass, and clover are the prin­ iron, and are very low in phosphorus. Manganiferous ore, used cipal crops grown on it. to some extent for spiegel iron, occurs in places. A specimen Clays occurring with the deposits of iron ore described above The De Kalb soil covers the areas of the Tusearora, Clinton, analyzed by McCreath had the following composition: are utilized for making fire brick, converter linings, and saggers Wills Creek, Oriskany, Hamilton, Portage, Chemung, and for pottery works. Their origin and mode of occurrence have Pocono formations, a total area greater than that occupied by Analysis of manganiferous ore from Bloomfield mines been already described in connection with the ore deposits at any other soil. Except in the areas of the Tusearora and the Iron _.______...._..... ___.__..____ .__..__..___.______. 22.700 Oreminea and Ore Hill. (See pi. 27.) Their composition is Ridgeley, the soil is predominantly a gray clay loam^ including Manganese-.-.. ...,..__..___.. ___.--.-...-...... ____-_-_..___--_..__-.. 37.611 shown below. Sulphur ...... -.- -____..____.._..____-.._._...... ___-__.-__-_-.- .018 smaller areas of silt loam and sandy loam, with or without slabby Phosphorus ____.._ ..._..-____. ______.043 Composition of clay mined at Oreminea fragments of sandstone, which are abundant in places. The Alumina _____.....___ ... .___..______-___-.-_--- _..._____ .144 [Average of 4 analyses. Aiithority, J. K. McLarmahan, Jr.] Lime_-__....__...... - ..-...... __. _._...___ .470 soil is 6 to 10 inches thick; the subsoil in most places is a hard, SiKca______._..______...___ -_-__._--.._..___-_ .. 59.275 tenacious clay or sandy clay with abundant shale and sandstone Millerstown ore bank. The Millerstown or red-ore bank, on Alumina..._..______.._..-_-.______--__..____--___ _...... _-._ 28.875 Ferric oxide__-_.______._.--__--___. .-_-...... _____-.._ 1.425, fragments. The soil of the Ridgeley and Burgoon sandstone the Bellefonte dolomite about 1 mile north of Henrietta, occu­ Lime ______..___-______-__.._-_-_-____-___. _.. .035 areas is sandy. The east slope of Warriors Ridge and The pied a generally shallow pit, but according to report shafts were Magnesia...___-_..-_._..____._..__-______----.___...____ Trace Barrens of the Trough Creek Valley have soil of this type. Water (combined) ______9.65 sunk more than 100 feet without striking rock, although around Soil of the Tusearora quartzite ridges is sandy and full of or the borders of the workings the rock is only a few feet below 99.260 covered with boulders and in places destitute of vegetation. the surface. The ore, a dark-brown limonite, is coated with The deposits of clay are too irregular in thickness and areal The De Kalb areas, where arable, produce good crops of cereals brown clay, from which it was called red ore. A specimen extent to permit any reliable estimates of quantity. The main and grass and are good grazing lands. analyzed by McCreath contained 54 percent of metallic iron. bodies so far as known are at Ore Hill, Oreminea, and the old The Upshur soil is the red soil of the red shale and sand­ Henrietta mine. The mine at Henrietta was an open cut 600 Rebecca mine. Clay has been shipped from the deposits at stone formations the Juniata, Hampshire, and Mauch Chunk. feet long, 200 feet wide, and 60 feet deep, mainly in Nittany Ore Hill and Oreminea to Pittsburgh for making brick and to Very little of the Juniata area is arable. The Upshur is a clay, dolomite near the east Henrietta fault, along which the Nittany east Liverpool, Ohio, for making saggers. Shale from South silt, or sandy red loam 6 to 12 inches thick and is likely to is in contact with the Reedsville shale. The deposit probably Altoona and Eldorado has been used to make common brick. contain many fragments of red shale. It appears to grade gen­ occupied a solution trough in the dolomite on the west side of At south Altoona shale from the Marcellus and the lower part erally into a clay subsoil at the depth of 2 to 3 feet. Where the fault. It consisted of clay and ore, without sand, sandstone, of the Hamilton formation, together with the overlying 10 to 12 arable it is productive, bearing good crops of cereals, grass, or chert. The ore is stained black in the upper part and is feet of creek wash clay, sand, and gravel was used. The potatoes, and fruit. The Mauch Chunk soil of the Trough called black ore. Some manganiferous ore was present. The shale and overburden were mixed in equal parts. At Eldorado Creek Valley is especially productive naturally. average composition of washed ore from the depth of 50 feet is 200 feet of soft drab or brown shale of the Harrell above the The colluvial soil known as the Holston soil is that upon the shown in the table below: Burket black shale member as well as the basal 100 feet of flood plains of the streams, mapped and described as alluvium, Composition of the Henrietta iron ore green sandy Brallier shale immediately overlying the Harrell and consists of the finer material from many original sources [Analysis by A. S. McCreath] shale, was utilized. The product is a strong common brick deposited from suspension in the stream waters as they have Sesquioxide of iron___.._____-, .._..___.._.._____..___ 60.000 that is sold in the surrounding country. overflowed their banks. It is a brownish sandy loam of con­ Sesquioxide of manganese... -_____._..... _ _.. _ _..._ _ _ --__-- 3.517 SAND siderable depth. Here and there it may contain a little gravel. Alumina 2.321 Owing to its manner of origin it is the most fertile and most .270 Deposits of sand suitable for mortar and cement are common Magnesia ____.. ..__... .398 easily tilled of the several soils. The market-gardening areas Sulphuric acid ______.162 in the areas underlain by the Gatesburg formation. At an old from Altoona to East Freedom are on Holston soil. Phosphoric acid. ___._. .822 pit half a mile southwest of Williamsburg the sand is 30 feet Water ______..-__.... 11.181 WATER RESOURCES Insoluble residue _____ 20.590 thick, and there is much sand on the surface of the ridges at Ore Hill, Oreminea, and Henrietta. Sand occurs throughout 99.211 Surface water. The mean annual precipitation of the region the iron ore bearing deposits, and a little has been taken out at is approximately 40 inches. The large and medium-sized Metallic iron______42.00 Metallic manganese. 2.449 Ore Hill and Henrietta. The Ridgeley sandstone of the Oris- streams maintain a moderate flow even in times of drought. Sulphur .._.__--____-- .065 kany group, being in part calcareous and generally loosely Stream-gaging stations are maintained on Raystown Branch Ph osphorus. _____..__ .359 cemented, yields much loose sand on its outcrop, and being soft of Juniata River at Saxton, on Great Trough Creek near and friable is also readily reduced to sand by crushing. On Other mines. Deposits of limonite, apparently small, are Marklesburg,O' and on StandingO Stone Creek near Huntingdon.O 3 6 associated with the Trough Creek limestone member at the Warriors Ridge the Ridgeley is about 100 feet thick and is The streams in or heading in Morrison Cove are fed by springs bottom of the Mauch Chunk formation in Trough Creek Valley. favorably situated for quarrying." Sand quarries at Brumbaugh and are to a large extent independent of the weather. These Ore of good quality was seen at a point 1 mile southwest of and Aitch have been worked on a considerable scale. At streams, too, maintain the water in Frankstown Branch of the Calvin. There is some manganiferous ore at the base of the Mapleton, a few miles southeast of Huntingdon, the Ridgeley Juniata River. There is an abundant and reliable supply of east slope of Terrace Mountain, 1 mile north-northwest of is a valuable source of glass sand. The flood-plain deposits water for the present industrial needs of the region. Holli­ Round Mountain, supposed to be the source of the manganifer­ along Frankstown Branch near and north of Reese supply a daysburg and Altoona obtain their public water supply ous ores used at the old Pattersori Furnace, near by. The old good molding sand, utilized largely in the car-wheel foundries from Blair Gap Run and Burgoon Run, perennial streams of workings extended over an area of but a few acres, and the of the Pennsylvania Railroad at Altoona. excellent soft water, which head upon the forested Allegheny depth to the top of the Burgoon sandstone member of the SOIL Front. Roaring Spring, Martinsburg, and Williamsburg ob­ Pocono formation is probably only 2 to 10 feet. tain their water from springs and natural drainage upon the The soil of much of the Hollidaysburg and Huntingdon Origin of the deposits. From their occurrence in deep sides of Tussey, Dunning, and Loop Mountains that face Mor­ quadrangles is residual that is, it has been derived from the depressions in the rocks and from the intermixture of sand, rison Cove. subjacent rocks by disintegration during the long course of clay, and. ore it seems probable that the deposits are residual Ground water. Water for household use can be had almost weathering to which they have been subjected. On the lime­ masses that accumulated where found, during a long period of anywhere in the area from shallow dug wells. Drilled wells stone areas the soil is the insoluble residue from limestone and denudation. It appears probable also that the present rock also are numerous, and most of the new wells put down are of dolomite, the calcium and magnesium carbonates having been basins holding the deposits are old sinks or caves that have this type. The water-bearing formations that appear to be removed by solution. Some of the soils are colluvial that is, gradually silted up after their outlets were clogged. The sinks most productive for drilled wells are the Cambrian and Ordo- they are a mixture of soils from different rock formations. may have been in former times foci of drainage for consider­ viciau limestones and dolomites, the Clinton formation, Cayuga Thus, on the slopes of the ridges rock waste from the higher able areas, from which the clay, sand, and ore were collected. group, Helderberg limestone, Shriver limestone, and Ridgeley part has been washed downward upon the lower part of the The materials were rudely assorted, and the iron was more or sandstone. Two wells at Hollidaysburg and three at Hunting­ slopes occupied by different rock formations. In places along less disseminated through them. Subsequently the ore was don have a small natural flow. 37 It is possible that additional the west base of Tussey Mountain, for example, the clay soil of concentrated by segregation within the clay. It is of interest flowing wells could be obtained at Huntingdon. Structure the Ordovician limestones and dolomites on the lower slopes is to note that in England are extensive deposits of similar favorable for an artesian basin exists in the Broadtop syncline, mixed with clay and sand from the Reedsville, Oswego, manner of occurrence in what are called "swallow holes." in Trough Creek Valley, where the Burgoon sandstone member Juniata, and Tusearora formations cropping out on the higher of the Pocono formation crops out in large catchment areas on COAL parts of the mountain. both sides and dips beneath the impermeable Mauch Chunk According to the classification and nomenclature of the A small synclinal area of less than a square mile at the north shales in the bottom of the valley. In this basin flowing wells Bureau of Soils, 35 the soils of the quadrangles include five end of Rocky Ridge, in the southeast corner of the Huntingdon might be obtained at depths less than 1,000 feet. kinds the Morrison, Hagerstown, De Kalb, Upshur, and quadrangle, contains three workable coal beds in the Allegheny At Williamsburg and Roaring Spring there are large springs; Holston. The Holston is a colluvial soil. The Morrison soil formation, as shown!below. that at Williamsburg issues from beneath the Gatesburg dolo­ covers the ridges underlain by the Gatesburg formation. It is Ft. in. mite, and that at Roaring Spring from the Nittany dolomite. Not exposed. described as consisting of 6 to 12 inches of sandy or clayey The main source of the great volume of water in both is prob­ Coal, Dudley (Lower Freeport?).-______4 8 loam with reddish or yellowish sandy and clayey subsoil, Not exposed______-..______..__---.____.___.._._... 100±. ably the Gatesburg formation, which crops out to the south of Coal, Barnett (Lower Kittannmg).______.._____ 3 6 generally low in humus and water. It is little cultivated but Not exposed__-...____.....___- -.-_-__-_--..... _. ._.. 45 bears a good growth of timber. 36 Discharge records have been given yearly in the Geological Survey Coal, Fulton (Clarion)______..______._. (5 Water-Supply Papers, "Surface water supply of the United States, part 1, Not exposed, about...... __ _.. ...______30 The Hagerstown is a limestone soil overlying the limestone North Atlantic slope basins," as follows: Raystown Branch of Juniata River Sandstone, Pottsville__...... __..-__.._ --__.____..___ 189 and dolomite formations of Morrison Cove, except the areas of at Saxton, October 1918 to September 1921 and October 1931 to date; Great the Gatesburg, and overlying the Helderberg and Tonoloway Trough Creek near Marklesburg, October 1931 to date; and Standing Stone Sections at other localities in the Broadtop Mountain field, Creek near Huntingdon, October 1931 to date. Records are given also in published by Gardner, 34 show that most of the rock that lies limestones outside of Morrison Cove. The soil is essentially a reports of the Pennsylvania Department of Forests and Waters for Rays- clayey loam of tawny color, 6 to 10 inches thick, with a stiff town Branch, August 1911 to date; Great Trough Creek, January 1930 to between the coal beds is shale. The coal from the Fulton and date; and Standing Stone Creek, October 1929 to date. Barnett beds is lustrous and soft and has a prismatic cleavage. clayey subsoil of uneven thickness, in most places 3 to 6 feet, 37 For further information see Lohraan, S. W., Ground water in south- resting upon limestone. In areas underlain by the Nittany and centi-al Pennsylvania: Pennsylvania Geological Survey, 4th ser., Bull. W 5, 33 Platt, Franklin, op. cit., pp. 214-213. 1938. This report contains a description of Blair and Huntingdon Counties 34 Gardner, James, Pennsylvania Top. and Geol. Survey Comm. Kept. 35 A reconnaissance soil survey of south-central Pennsylvania, U. S. and includes tables of wells for each county and a map showing the locations 10, p. 25, 1913. Dept. Agr. Bur. Soils, 1912. of the wells. Hollidaysburg -Huntingdon 20 i each. These outcrop areas are deeply covered with coarse sand, yield more than 4,000 gallons a minute, and Roaring Spring extensively used for domestic supplies, particularly in some of which acts as a natural reservoir for the water falling upon it, about 5,500 gallons a minute. These springs supply paper the valleys that are bordered by high ridges, and the formation itself is composed of rather open-textured mills at Williamsburg and Roaring Spring. Another spring Most of the water from wells and springs is of good quality, dolomite and sandstone, through which the water finds an easy at Royer, which issues from the Bellefonte dolomite, has an but some of the limestone waters, especially from the Cayuga passage. The Big Springs at Williamsburg are reported to estimated yield of 1,500 gallons a minute. Small springs are group, are too hard for use in boilers.